Appropriate Spacing for Different Design Speeds (Danish Guidelines)
10-20 km/h (5-10 mph) 25-55 m (80-180 ft)
30 km/h (20 mph) 75 m (250 ft)
40 km/h (25 mph) 150 m (500 ft)
50 km/h (30 mph) 250 m (820 ft)
L. Herrstedt et al., An Improved Traffic Environment—A Catalogue of Ideas, Danish Road Directorate, Copenhagen, Denmark, 1993, p. 59.