By W. Martin Bretherton Jr., P.E. (F)
I hope you have had a great holiday season and I wish you a prosperous new
year. By the time you read this, it will be time to attend the Transportation Research Board (TRB) Annual Meeting. If you have never attended this meeting, you are missing a great opportunity to see what research is being done in the
United States and world on any transportation-related topic. It is also a great opportunity to network, with
more than 6,000 engineers attending the meeting.
I would like to highlight some important activities from the ITE Board of
Direction and Traffic Engineering Council (TENC) Executive Committee (EXECOM).
- ITE is reorganizing its staff as a result of
Shelley Row's return to U.S. DOT. There will be domain specialists assigned to the Traffic
Engineering Council as well as to each of the other five technical areas.
- The consultant project is underway to update the
Guidelines for the Design and Application of Speed Humps, An ITE Recommended
Practice. A draft report was submitted to the technical oversight committee for review in October. The final report is scheduled to be completed in 2007.
Our newsletter received a letter to the editor. The letter was critical of an article published in the TIPS column in the last edition of the newsletter. The article was titled “Standardizing the Use of HCS in Traffic Studies.”
The letter is printed below, along with a reponse. I am happy to see some feedback from our membership on what we are publishing. Obviously, nobody likes criticism, but I think this will allow us to have a good discussion within the profession on this topic. I hope we can have dialog on other topics of interest to the membership. I would like to encourage you to provide feedback to us on issues of interest to you.
The EXECOM sees the TENC listserv as the best way to communicate and serve our membership. There are
more than 480 TENC members presently using the listserv. The TENC listserv is by far the busiest of all councils in ITE. If you want to join, please go to the ITE
Web site (www.ite.org/councils/TENC/index.asp) and go to the TENC section.
The listserv is listed under the “Discussion Group” heading. It is a great way to get answers to your technical questions from your peers.
I would like to thank the EXECOM members for another great year serving our membership. Every district has at least one person serving on our EXECOM except District 8. If there is anything we can do to enhance your membership in ITE and/or the
TENC, please let me or the EXECOM member in your district know.
TO THE EDITOR
I am a long-time member of ITE and member of the Traffic Engineering Council. This letter is to express my strong objection to the article on page 6 of the fall issue of the Traffic Engineering Council Update: "Standardizing the Use of HCS in Traffic Studies." In referring to instances where the HCS analysis was "cooked," the article states that "These suburbs must be aware of this practice." I find that statement terribly offensive, because it gives the impression that traffic engineers typically present false results. Though I have seen a few such instances myself, I find that such unprofessional conduct is the rare exception, not normal "practice." In the next issue of the Update, I would ask you to correct the misleading impression you created with the statement that suburbs must be aware of this practice.
Another major issue I have with this article is your recommendation that default HCS values be used in all instances. In my judgment, that recommendation defies logic and, if implemented, would lead to erroneous results where actual conditions regarding a particular parameter are substantially different from the default value. For any particular instance, the most accurate analysis results obviously will be achieved when local data and traffic characteristics are used to the maximum extent possible. The notion of all studies being based on the same foundation is meaningless if the foundation is invalid for some locations. Again, I would ask you to correct this recommendation in the next issue of the Update.
Thanks for your attention to these important items.
There was absolutely NO intent to convey that all TISs are “cooked.” Are there some that are intentionally cooked? Yes. Is this getting more common? In some areas of the
country, yes. I have seen HCS analysis where the "after" analysis was manipulated to stay within the acceptable levels by removing the all-
red times from only the "after" analysis. Any of us involved in TIS review have seen this go on. Are some simple mistakes? Sure. Are some an attempt to please a key client to keep their company happy? Sure. I've even had it admitted to me by one engineer in our profession. . Are there
gray areas that can be argued back and forth and not be considered unethical? Absolutely. In consulting, when your boss says you haven’t brought enough work to the firm, the temptation to please a client in any way possible is strong. Small towns and suburbs do need to be aware that there are developers and bosses that successfully pressure engineers to "make it
work." Just as there are ethical problems in professions where life and death is a daily thing (surgery, for example), there are also problems in our industry as well and people need to be aware of this.
After discussing the wording of the article in the last newsletter with others, the feeling is that the choice of the word "practice" in the sentence in question may have been poor. The word "practice" was meant to refer to the "practice of cooking..." not the overall "practice of our profession" or the "practice of impact analysis". If anyone had intended to say that a part of our industry was totally corrupt, yes, a full retraction would be undertaken.
Concerning the article about default HCS values, a clarification is needed. The article’s intent was not to say that someone couldn't come forward with data to show that a default was not appropriate in a particular case. The HCS default values were based on logic that they are within an acceptable range in the majority of cases. No one is paying any consultant or taking their own time collecting field data to nail down ALL values that are used in HCS for every individual
TIS. Most know that the defaults are good in most cases and do not spend money or time to tweak them. The issue is that, over and over, people are changing items in an analysis without any backup data. They simply state "engineering judgment" when asked about the issue. That is appropriate for some things in our industry, but not when a TIS for a 500-
acre shopping center is the supporting documentation for a half- million dollars in infrastructure improvements. My attempt at brevity did not convey the true intent of the article.
I'm not a writer. I'm an engineer who, arguably, has some writing skills. My apologies for wording that may have not conveyed my true intent. I appreciate your comments and will learn from them as I write for the next newsletter.
TOPICS ON THE TRAFFIC ENGINEERING COUNCIL LISTSERV
By Jim Harris (M)
The TENC listserv was again very busy this past quarter, with almost 500 postings.
The quarter started with a discussion first focused on street tree planting for “pleasing public spaces” and then on the differences between one urban designer and transportation engineers. I suspect the answer, if there is one, falls somewhere between the extremes expressed, so this discussion got people thinking. It looks like the subject for a paper. Go to the September 18, 2006 postings to the listserv at
list.ite.org/cgi-bin/wa.exe?A1=ind0609&L=itetraffic under the innocuous subject of “Streetscapes” for the full exchange.
Here are some of the questions posted:
- “We are currently working on a traffic safety project which includes investigating the safety benefits of the installation of illuminated street signs. It has been suggested that there may be safety benefits during night time operations due to improved driver guidance. The benefits may be mostly for elderly drivers and for drivers un-familiar with the area (tourist destinations). Any information that the group may be able to provide regarding the application of illuminated street signs will be greatly appreciated.”
- “I recall a mention recently insinuating that there has not been conclusive evidence indicating that black signal heads improve operations over yellow or green signal heads (or whatever other colors an authority may use). Is anyone aware of any studies which have examined the effectiveness of different-colored signal heads?”
- “We have done numerous ‘drive time’ studies for all kinds of uses. However, the request I got today was a new one. We have been asked by a hospital client that is moving to a new site to conduct a study for ambulance response times (drive times) from various intersections to both the existing and proposed campus locations. As much as I want to borrow an ambulance and go blazing through town with the stopwatch running, something tells me that's just not the right thing to do. Have any of you done a similar study? How does one account for the reaction to the sirens/lights and the impacts of emergency vehicle preemption if you are driving a regular passenger car?”
- After a discussion of a problem where decision- makers wanted an ill-advised improvement, the following question was posed: “My proposal is to have a consultant (borrowing a phrase from a great organizational psychology textbook, ‘...to lend the aura of outside expertise’) with significant pedestrian safety and tort liability experience review the project proposal and develop an alternatives analysis. I would want someone that also has the ability to persuade a City Council and/or staff to a position that would have otherwise not been considered……Are there any pitfalls to this approach? Any other suggestions? Do you have any recommendations for such a consultant, either as a prime or as a sub to a local design firm (not yet selected)?”
And from Kuwait:
- “In Kuwait we will be working on projects for the planning and design of new cities. These cities are planned for 250,000 to 500,000 population. These projects will involve development of traffic model (sub-model of the existing Kuwait Traffic Model with external zones). We will be responsible for establishing the roadway network classification and other infrastructure for various land uses. Considering the whole city there will be lot of roads and I want to minimize my time in establishing the roadway corridors. Will it be practical to carry out the capacity analysis for the roadways and the intersections for the peak (AM or PM) that reflect generally heavy flows overall from the model output or it will be necessary to carryout capacity analyses for both peaks AM and PM for the whole city roadways and then decide the corridors. My approach would be to go for that peak that generally reflect heavy flows and accommodate certain movements at the intersections that show heavy flows in the other peak and call out the facility is designed either for AM or PM peak. This approach is usually adopted for highway projects now will it be applicable for the entire city. Please provide comments from your experiences.”
- “I will soon be advising the relevant authorities over here for setting the requirements for the Traffic Impact Studies
(TIS) as TIS is new in Kuwait. I would like to have suggestions from TIS experts that will it be fine to consider public transport, pedestrian movement and parking requirements due to the proposed development as part of the
In addition to the above, trip generation and parking requirement inquiries
included the following:
- Rates for drive-through restaurants without indoor seating
- Rates for UPS stores
- Rates for golf villa and village center
- Rates for accessory dwelling units
- Rates for indoor/outdoor water parks including parking demand
- Definition of local, regional and interregional trips
- Rates for complimentary uses on a medical campus
- Rates for harness racing facility with casino and slot machines
- Rates for coffee kiosk in strip commercial shopping center
- Rates for “business” banks
- Rates for 20 to 50,000 attendee motor sports facility
- Hospital parking
- Parking at community/recreation center with a park and pool
- Underground parking, specifically stall sizes and turn templates
Some software related inquiries included:
- ACS Lite signal system software
- Traffic circle (roundabout with stop control?) performance using Synchro
- Roundabout analysis using aaSIDRA
- Availability of “reliable” accident prediction model
- Pavement analysis software
Traffic signal questions included:
- Use of emergency vehicle preemption, especially with permitted left-
turn phases and GPS provisions
- Number of traffic signals per technician and sign/paint technicians per centerline
- Flashing yellow arrow cabinet modifications and flash rates
- UPS vs. generators for traffic signal power failures
- Traffic signals and collision rates on 5-percent
- “HAWK” pedestrian crossings
- Traffic signal technician salary ranges
- Energy consumption and heating of controller cabinets
- Database and maintenance tracking system
- Warrants using predicted ADTs and future roadways
- Permissive left turns at signalized intersections along high speed roads
- Use of vibrating tactile arrows on pedestrian buttons at all red/Barnes Dance pedestrian locations
- Use of 5.9 GHz and 915 MHz systems for signal priority and preemption
Other questions involved: vehicle occupancy rates; specifications for countdown pedestrian signals; four-way to two-way stop control conversions; safety of elevated vs. at-grade vs. depressed roads; definition of terms i.e. background traffic vs. projected traffic; street name signing standards; pedestrians and high speed; limited access roadways; staggered limit lines for left; through and right turn movements; school zone boundaries and controlled crosswalks; truck route signing for specific destinations; logos on street name signs; reversible lanes; wide lanes vs. narrower with bikes; adding lanes opposite a narrow roadway; stop signs as speed control devices (again?); suits regarding citations for violating unwarranted stop signs; fire hydrants and collisions; markings for nighttime speed enforcement by aircraft; stop controls vs. school access problems; stop sign controls near signals; maximum lane widths; striping cost comparisons; roadway widening for perceived need; HOV lanes on non-freeway arterials vs. significant turning volumes; turning lane installation criteria; and finally, right turns on red vs. pedestrian activity.
As a courtesy to others, please include a signature with any posting to the listserv. It helps others get an idea of your perspective on your question or comment (i.e. consultant versus agency, east coast versus west coast, north versus south, rural versus urban, big city versus small town, etc.). Include your name, title, agency or company name, phone number and email address so someone can contact you.
Retrieve past postings to the TENC listserv at list.ite.org/lists/itetraffic.html. You may have to register and obtain a password but it
will be worth your time.
If you don’t use the TENC listserv and wish to, go to list.ite.org/lists/itetraffic.html and click on the “Join or leave the list (or change settings)” link.
TIPS AND TRENDS IN
Compiled by Jim Harris (M), with submittals by Martin Bretherton (F) and John Gallagher (M)
- MUTCD: The NCUTCD met in July 2006 and it looks like the next edition of MUTCD will be delayed from 2008 to 2009. Also, California just adopted the California
MUTCD, which takes MUTCD 2003 and adds California’s changes to it.
FHWA has a discussion group for issues that concern
MUTCD. It is very interesting and timely. It may answer some of the questions you have regarding items in
MUTCD. Go to: knowledge.fhwa.dot.gov/cops/opspublic.nsf/home. Look at “What’s New” to find some of the recent items discussed.
To participate in the discussions you need to click on “email
notification” and provide some information.
- U.K. hard shoulder trial not a safety risk, say consultants: Recent speculation that allowing motorists to drive on the hard shoulder of the M42 in the
United Kingdom will risk the safety of motorists is unfounded, according to transport consultants Faber
Maunsell, who undertook extensive research on the subject:
The September 2006 hard shoulder running trial on the M42 has been condemned by some commentators. However, the development of the hard shoulder as an operational lane is based on extensive research into the use of the existing hard shoulder.
Peter Yendall, highways director at Faber Maunsell, comments: “Allowing drivers to use the hard shoulder at certain times has been introduced to reduce the level of congestion, and while there is a remote chance that a stoppage will occur within the carriageway, this is unlikely to erode the journey time benefits. To say that allowing drivers to use the hard shoulder is unsafe denies the research, which has led to the implementation of this practice here and abroad.”
Set criteria must be met before a stretch of motorway is deemed appropriate for hard shoulder running. Suitable CCTV surveillance is one condition that must be met, to allow immediate emergency service assistance in the event of an incident. Additionally, the width of the motorway in question must be large enough for vehicle queues to be squeezed in order to allow emergency vehicles to pass.
Yendall adds: “The operational benefits of allowing drivers to use the hard shoulder in times of congestion or following an accident on the main carriageway can significantly outweigh the use of the hard shoulder to accommodate intermittent stoppages.”
-Adapted from September 2006 ITS International
- Traffic Safety Facts: 2005
Annual Report: The U.S. National Highway Traffic Safety Administration’s National Center for Statistics and Analysis has been released. It is a compilation of motor vehicle crash data from the Fatality Analysis Reporting System and the General Estimates.
The Web address for the report is www.trb.org/news/blurb_detail.asp?id=7037.
- Making ABS brakes screech: A positive invention, ABS brakes, have one major flaw, according to Larry Bunker. They kill! The screeching
tire sound emitted when non-ABS brakes are engaged is lost in an ABS system. However, a new invention artificially replaces the blood-curdling screech of
tires in a panic stop, allowing pedestrians to jump out of the way and avoid being hit.
The trigger to inventing this device was when Larry Bunker (co-inventor) slammed on his brakes just as a co-worker jumped out of his truck into Larry's pathway. The loud screaming tire sound created when Bunker hammered his brakes to stop was just enough warning to allow his co-worker to jump out of the way to safety. It was at that moment that he realized that if he had had ABS brakes instead of non-ABS ones, he would have silently run over his friend.
According to Bunker, his invention, for which he has obtained a U.S.
patent, provides a “win-win” situation. “Automobiles can continue to enjoy all of the benefits of ABS brakes without losing the benefit of an audible warning. Car manufacturers, safety agencies, and insurance companies would all benefit exponentially from this invention," Bunker states.
- U.S. DOT
strategic plan: The U.S. Department of Transportation has released its strategic plan for fiscal year 2006-2011. The plan is designed to build on the progress made by the DOT in improving transportation in the
United States and examines how the department will work to lay the foundation for a new transportation model that will be needed to support America’s economy in future years. The department has set policy goals in the areas of safety; reduced congestion; global connectivity; environmental stewardship; and security, preparedness and response.
The Web address is http://www.trb.org/news/blurb_detail.asp?id=7025.
- Just push the button: MetroTV is a simple-to-use service
that involves users downloading a small piece of software onto their mobile phones. Thereafter, at the push of a button, it provides them with a full, interactive map of their chosen region and live, 24/7 access to local authorities' databases of relevant information. mxData Ltd., which developed the service, signed many UK local authorities to the service and aims to roll out the service internationally over the next few years.
In addition to the live information provided by municipalities for all different modes of transport, the company has partnered with TeleAtlas to be able to supply highly accurate street-level maps with a huge database of points of interest information. The result, it says, is a 'must-have', free-at-the-point-of-use service for the public.
For more information, visit www.mxData.co.uk.
magazine: The University on California Transportation Center released the latest issue of its
ACCESS magazine. The semi-annual publication highlights selected research projects funded by the center and research findings judged likely to interest a diverse audience of transportation professionals and public officials. Stories in this issue include “We're All Transportation Planners,” “Dispatch From London,” “Asilomar Declaration on Climate Policy,” “Down to the Meter: Localized Vehicle Pollution Matters” and “Stuck at Home: When Driving Isn't a Choice.”
The Web address is www.trb.org/news/blurb_detail.asp?id=7040.
- Honda's safety drive for motorbikes: The bright yellow motorbike which was shown by Honda at a recent trade show is part of the company's contribution to Japan's national ASV-3 program, which is looking at how to improve the safety of all types of vehicles.
It features three different technologies aimed at reducing collisions – inter-vehicle communications, a two-camera sensing package and conspicuity-enhancing lighting.
The ASV series of projects has been running for several years, says Chief Engineer Kazumitsu
Kushida: "The follow-on ASV-4, which will look at wide-scale testing from 2008 and deployment thereafter, will include vehicle-to-infrastructure communications but ASV-3 concentrated on vehicle-to-vehicle because of the need to ensure the fastest-possible market penetration."
Although market penetration for the communications systems will to an extent also be dependent on market penetration, the conspicuity enhancements could have a more immediate impact says Pascal De
Jonge, who is responsible for motorcycle safety homologation:
"The layout of the front of the bike was based on research which identified humans' sensitivity to facial images. It encourages faster recognition and safety. Also, the inclusion of multiple lights gets around a traditional problem with motorcycles--that it is very difficult to judge how far away a single light source is. By having two lights, like on a car, other road users are better able to judge the bike's distance and closing speed."
- Directions: The University of North Carolina
(UNC) Highway Safety Research Center (HSRC) released the latest edition of
Directions. Look for articles on what factors contribute to large truck crashes, evaluating the effects of
North Carolina’s teen driver cell phone restriction and Web-based resources developed for Safe Routes to School.
The Web address is www.trb.org/news/blurb_detail.asp?id=7024.
- European road safety measures trigger debate: The
European Community is pushing for the mandatory use of daytime running lights for all vehicles as a safety measure. However, this move has attracted many negative comments, saying that the measure will be ineffective, will increase vehicle exhaust emissions and may pose a threat to vulnerable road users. The UK-based Motorcycle Action Group
(MAG) has blasted the idea, saying that it will offer little safety benefit for car users but will be potentially dangerous for motorcyclists in particular. The
U.K. government also opposes the idea, saying the measure will be counter-productive and risk increasing levels of powered two-
As many motorcycle riders use headlights during daytime to increase visibility, requiring car drivers to do the same could lessen the benefit for vulnerable road users, according to
MAG. This view has been echoed by the UK's road safety minister, Dr. Stephen
Ladyman. Given that motorcyclists are already at risk, MAG argues that this legislation could actually increase accident rates. MAG suggests that a more effective safety strategy would be to improve the visibility from passenger vehicles, as well as ensuring manufacturers redesign the front end of their cars to lessen the impact with a vulnerable road user.
In a separate development, a report was published by the UK's Department of Transport stating that users of small and mid-sized cars face higher risks of death or serious injury on Europe's roads than users of larger vehicles. This report echoes an earlier
U.S. study that people inside large 4x4/SUV type vehicles have a lower risk of injury in a collision. Drivers of small-medium sized passenger cars face a one in 200 risk of being killed in a collision. By comparison, drivers of large 4x4 or people-
carrier type vehicles face a one in 10,000 risk of being killed, according to the survey. Certain models of small-medium sized cars available in Europe came in for particular criticism, although a few small vehicles were noted for their high safety standards in crashes.
-Adapted from World Highways
- Lighting the way:
World Highways editor’s note: Reader and industry professional William Wellman wrote a concise and comprehensive response to the foregoing news item regarding the use of daytime running lights on vehicles. We believe debate on safety issues is beneficial, so we are publishing his comment as a special feature with his permission.
The addition of daylight running lights on all motorized vehicles will improve highway safety. In the U.S., the use of daylight running lights was first affected by large tractor trailer rigs. They turned on their lights for safety in an effort to be more visible. The records reflect that the use of daylight running lights did increase their safety and soon legislation was passed to require the installation of these types of running lights on all new model vehicles. The use of automobiles with daytime running lights makes it no more dangerous to motorcycles, in fact, just the opposite. A cyclist who can see a car coming will be more prone to get out of the way.
The presence of additional lighting can help anyone in the environment discern the location of the object in question. This is true for an operator of any type of machinery as well as for pedestrians.
Cyclists have no less stature on the roadway than anyone else though. Good car drivers give cyclists more space in the roadway. Bicycles have different stopping distances and turning radii and need to be treated with respect. Due to their very nature they are more prone to be in the blind spot of the larger vehicle. With the graying of the baby-boomer population there is also a dramatic increase
in deaths associated with motorcycles in the United States. Accident statistics suggest that many of the deaths are caused by inexperienced riders on powerful motorcycles. This has brought about a new phrase of donor-cycle as a result of the number of fatalities.The real question with the cyclist is “how can we make the environment safer?” Respect for the cyclist is one way. Training in operation is another. Reduction in roadway aggression is still another.
Disrespect or intolerance of cyclist for motorist or vice-versa only leads to death for the cyclist. Society must develop safeguards for all users of the roadways, and remember that “driving is a privilege.” To treat driving as a “right” only makes the individual defensive and aggressive.
Daytime running lights, while not the end-all, be-all solution, does add a measure of safety. To argue that they will become commonplace and therefore will somehow reduce their effectiveness disregards the benefits. Driving is not and should not be treated as a commonplace everyday task. It is a complex issue and operation of machinery requires attention to detail. Disregard for the skills and attention
needed can be fatal.
-Adapted and published by permission from
Note from the editor: As a renewed large motorcycle rider, I am all too aware of the lack of visibility of me and my motorcycle. Will daytime lights for all make a difference? It’s hard to say. I, and all motorcyclists, need to ride as safely as possible and assume we are not seen because in reality we are not. I’d love for car (we call them cages) drivers to more cognizant of motorcycles but I’m still responsible for my own well being and must ride accordingly.
safety at midblock locations: The Florida Department of Transportation released a report that examines the role of crossing locations and light conditions in pedestrian injury severity. The report also includes a set of proposed guidelines for marking midblock crosswalks at uncontrolled locations along Florida’s state highway system.
The Web address is www.trb.org/news/blurb_detail.asp?id=7047.
- Gridlock for U.S. roads? With the U.S. population now topping 300 million, plans are being called for to tackle the growing problem of gridlock on the country’s road network. This represents a 50-percent increase in population since
1968. The number of licensed drivers has nearly doubled from 107 million to 199 million and the number of vehicle kilometers driven has nearly tripled. The American Road & Transportation Builders Association’s
(ARTBA) estimates that between now and 2043, based on current trends, highway capacity will only grow 9 percent. However, traffic levels will swell by 135 percent. As a result, the average motorist can expect to spend 160 hours stuck in traffic delays, or the equivalent of four weeks each year. This is a recipe for a gridlocked nation, ARTBA says, unless major steps are taken soon to add new highway and public transit capacity to accommodate future
- Smoking ban vs. transportation industry: Many times, laws have unintended consequences. In the last election, Ohio passed a smoking ban for public and business facilities. No big transportation issue with that, right? A major Ohio newspaper found this applies to company owned
tractor-trailers! It will be interesting to see if this has any affect on truck travel in Ohio. Link to article:
- Navteq launches full coverage map of Australia: Navteq has announced the immediate availability of its full coverage navigable map of Australia. With the release of Australia, Navteq maps now cover
six continents and 58 countries.
The map of Australia covers approximately 99 percent of Australia's population, is fully navigable and enables door-to-door route calculations and turn-by-turn route guidance. Detailed road network information, including a collection of up to 204 attributes such as one-way streets and turn restrictions, enables navigation systems to provide efficient routing.
To build the map of Australia, more than 45 field analysts from the United States, Europe and Australia spent more than six months driving more than 227,000 kilometers and collecting approximately 63,000 points of interest.
- Grant to launch connected vehicle proving center: The Connected Vehicle Trade Association
(CVTA) in the United States is to jointly develop and operate a new, one-of-a-kind laboratory to support global development efforts in intelligent transportation and vehicle communications with the Centre for Automotive Research (CAR). The
Connected Vehicle Proving Center (CVPC) is expected to play a pivotal role in substantiating future trends for vehicle wireless connectivity throughout the global automotive community.
The CVPC will be launched with a $3 million grant from Michigan’s 21st Century Jobs Fund. The grant is a part of a $6.9 million effort to develop the
center and includes the CVTA, CAR, universities, government agencies, automotive companies and automotive suppliers.
Initially, the CVPC will be made available to public and private entities as a reference environment for product evaluation and qualification. Over time, the center will evolve into a certification and validation
belt striping issues: Agencies in areas with snow frequently fight a battle to obtain good pavement marking performance. Over the years, states such as Michigan, Kentucky and others used "performance specifications" or warranties. A pavement marking contract would be bid and require the marking to perform to a standard (generally
retroreflectivity) after a specific length of time had passed since its installation. If the marking
does not perform to the specification, the contractor is required to reapply the marking or suffer some other consequence.
This seemed like a no- lose situation for transportation agencies. After time passed, it was clear that a pavement marking contract of any size would need a substantial amount of manpower to evaluate the markings post-application. Of course, many contractors disputed the findings if their markings were considered non-compliant with the contract. Many would evaluate the markings on their own and present contradicting data showing they were in compliance. This forced the agency back to the field to make a very thorough reevaluation of the markings. In the final analysis, even if the agency showed the contractor to be non-compliant; did they save money or improve the markings for the traveling public? Most felt they did not.
Some agencies, like Ohio DOT, gave up on the warranty pavement markings and opted for a less manpower intensive
solution. Require contractors to have a data logger on their pavement marking equipment. This logger records most critical aspects of pavement marking application such as material application rate (beads and marking material), truck speed, air/roadway temperature and many others. This guarantees their contract markings are installed to specification. The only manpower required is for someone to review the data log sheets the contractor submits for specification compliance.
However, for this system to work, you must have a good prequalified or specified list of materials. If not, you only guarantee that questionable materials are being applied correctly. So if you continue to have issues with pavement marking performance, consider this another tool in your
- Tactile arrows: I think you can generally assume that blind or deaf/blind individuals who will be using the tactile arrow will cross one street at a time rather than making a diagonal crossing.
You'll need to install an accessible pedestrian signal (APS) device for each crossing and align the arrow in the direction of travel on the crosswalk. The APS needs to be near the crosswalk line; see MUTCD 4E.09 for placement information. Installation of stub poles (pedestrian pushbutton posts) may be necessary
to locate them appropriately. If you don't locate them appropriately, you've basically directed a blind person, who will need to stand with their hand on the device while waiting to feel the vibration, to begin
his or her crossing at the wrong place.
Each device also needs a pushbutton locator tone so blind pedestrians can find the device and arrow. You can also use a rapid tick audible walk indication, along with the vibrating arrow, from all devices at the same time. Pushbutton locator tones and walk indications just need to be audible from the beginning of the crosswalk; MUTCD says audible 6 to 12 feet from the pushbutton. On all the pushbutton-integrated APS currently on the market (ones with vibrating arrows), the audible indications respond to ambient sound, but adjusting them properly when installed is important and louder is NOT always better.
More information is available at www.walkinginfo.org/aps and
www.accessforblind.org or you can contact me privately at
Submitted by Janet Barlow, Certified Orientation and Mobility Specialist at Accessible Design for the Blind, in answer to a recent listserv question.
Published by permission.
SPEED LIMITS ON SUBURBAN MULTILANE HIGHWAYS WITH CURBS
By Jongdae Baek, Joseph E. Hummer, Billy M. Williams and Christopher M. Cunningham
When some two-lane roads with 55 mph speed limits are widened to four through lanes, curb and gutter
are installed to address issues such as access control, difficult terrain and limited right-of-way. Posted speed limits along such highway segments are typically decreased to 45 mph in North Carolina because of guidance in the AASHTO Green Book and elsewhere that vertical curbs should not be placed next to high-speed lanes.
Although much money is spent to improve such roadways, the results may be viewed negatively by the public, design professionals and law enforcement. Drivers may be unhappy about getting tickets or driving more
slowly; designers are unhappy about being blamed by the public; and police are unhappy about the increased enforcement burden. To help resolve such a dilemma, in this research, the team collected relevant data such as speeds and collisions on four-lane road sections with curbs that have 45 or 55 mph speed limits and non-traversable medians or two-way left-turn lanes. The team found that the speed limit does not seem to make an important difference in collision rates or severities for the roads the team examined. The higher speed limit also made relatively small differences in the mean speeds and speed variances observed. Considering all results, the researchers recommended that the North Carolina Department of Transportation continue its current policy of allowing 55 mph speed limits on four-lane roads with curbs on a selective, case-by-case basis.
The research was published in 2006 in the
Transportation Research Record: Journal of the Transportation Research
Board, Issue Number: 1969.
HOV LANES ON ARTERIALS
The following was an exchange on the listserv:
We have a 6-lane major arterial—which is also part of the national highway system—running through our community and giving access to most of the major traffic generators, including the main mall and numerous strip malls along the way. Signalized intersection spacing varies from about 300 feet to about half a mile and while accesses are not frequent between intersections, where they occur they can serve significant attractors such as malls. Daily volume along this road is in excess of 50,000
vehs. (the population of our region is about 170,000). The suggestion has been made that the outer lane be converted to an HOV lane, with well-spaced bus pull-outs to serve an express bus route. Does anyone know of similar HOV facilities elsewhere under non-freeway conditions and with significant turn volumes, or reports on the success of such facilities?
Harry Thompson, P.Eng.
Traffic & Transportation Engineer
City of Kelowna, BC, Canada
As noted by Bruce Newman, SR 99 in Washington has several miles of arterial HOV lanes. There are also arterial segments of HOV lanes on SR 522, SR 18, SR 181, SR 900, Airport Road in Snohomish County, and S. 212th Street in Kent. This is in large part driven by state and regional policies that make it difficult to get grant funding to widen to 6 lanes if it only improves GP traffic.
How successful these corridors are depends on one's perspective. Some segments are so short that their utility is limited. A few are not on major transit routes (but do serve major employers), but were it not for the HOV lanes, they would have not been funded, so some capacity improvement was considered to be better than none. Most were previously shining examples of a lack of access management. As they were widened, many had raised medians installed, which improved safety, but that would have occurred whether the lanes were HOV or GP.
Due to driveway spacing, enforcement is limited. There is also a need for uniformity on signing and marking, as well as what constitutes a violation. We met with our police and municipal judge to agree on a common definition and put out a brochure (contact me if you want one), but the State Patrol disagrees with some aspects of our guidance. Unfortunately, state laws on HOV lanes appear to be written for freeway HOV lane applications only, so there is a lot of room for varying interpretations.
Another topic that garnered a lot of discussion in design was bus pullouts. The state DOT is rather insistent about having them (at someone else's expense, of course), but the transit agencies hate them and the cities can't afford the right-of-way in many cases. I did a benefit/cost analysis that concluded for our average right-of-way expenses (no building takes required) and construction costs, we needed 8 buses an hour to justify the expense of constructing the pullout. It'll be interesting to see if this dynamic changes now that King County Metro received voter approval to run BRT on SR 99.
We haven't broken out our counts by lane yet to quantify how the lanes are being used, but casual observation suggests that they are best utilized during the evening peak and on weekends when AVO's are up anyway. Otherwise, they act primarily as continuous right-turn lanes, but the transit agencies sure like them. We hope that the utilization goes up as the system becomes more continuous, our modeling suggests that this will be the case.
Despite the perception of low utilization, the projects in Federal Way have not garnered much criticism for the HOV lane treatment. It may be that the business community feels that it has already adequately vented its collective spleen on the raised median and construction impacts, and the public has been so grateful for any congestion relief and aesthetic improvements that they haven't complained much about the treatment either. We have not yet had the temerity to convert a GP lane to
HOV, though. We have one six-lane segment where this was briefly considered, but queuing back onto the I-5 mainline is a daily occurrence as it is, so we did not want to exacerbate that problem.
City Traffic Engineer
City of Federal Way