It seems most studies of amber lights focus on whether cities are using them to gather revenue. The theory – and let's face it, sometimes the fact – is that the light time is so short that drivers end up tripping the red light camera and getting a fine. Conversely, a new study by the University of Cincinnati and Ohio Department of Transportation has taken a look at how drivers behave when they encounter a yellow light no matter how long it's illuminated.
More than 1,500 drivers were caught on camera in suburban Ohio as they approached high-speed intersections and entered the "dilemma zone." Without offering any hypotheses for the discoveries, a few of the most interesting finds were:
- Drivers in the left lane – the high speed lane – tended to stop for yellow lights, drivers in the right, slow lane, did not tend to stop.
- Longer yellow lights tended to have more drivers running them.
- If the street had a higher posted limit, there was a larger tendency for drivers to go through yellows – more drivers in 55 mph streets ran yellows than those on 50 mph streets.
- 18-wheelers ran yellow lights more than pickups, SUVs, light trucks and sedans. According to some police records, however, truckers weren't more likely to run or be cited for running red lights.
America's lack of high-speed lane discipline tends to put drivers of different defensive inclinations at different speeds in every lane no matter how many lanes there are. Part of making yellows more predictable has been installing countdown timers at crosswalk signals so drivers can tell how much time they have before the light turns yellow. In our experience, a fair number of drivers either hit their booster rockets and zoom through a green light or start slowing down before the light's even turned yellow. We imagine we'll be seeing more of this kind of research soon enough...
| Image: Corbis]