Ordinary Gweilo

I don’t drive in Hong Kong, but I do take buses, so traffic jams do affect me. One of the more baffling things about traffic jams is that there is sometimes no apparent cause – no accident, no roadworks, no car broken down in the middle of the road. The M25 (London’s orbital motorway), especially around Heathrow Airport, used to be one of the worst places for this problem. The explanation, as set out here is that:

Such jams start when a car slows suddenly to allow, for example, another vehicle to enter the traffic stream. Slow reaction times mean that instead of responding smoothly, the drivers behind such a vehicle often end up slamming on the brakes. That slamming propagates backwards, and before long the traffic is at a standstill.

One solution that worked well on the M25 was lower speed limits at the busiest times. This worked very well, and so a lower speed limit led to an increased average speed, amazing as that may sound.

The next step is apparently Adaptive cruise control (ACC), which adjusts the car’s speed to match the vehicle in front. The benefits are that gaps between vehicles can be reduced without compromising safety, and vehicles with ACC can reduce their speed more rapidly without slamming on the brakes (which is one cause of these mysterious traffic jams).

The intriguing thing is that according to research, even if only 20% of cars on a road had ACC installed and working, it could still improve traffic flow.

The problem I can forsee is that the car in front may not appreciate someone following them so closely. How can you tell whether it is tailgating moron or someone with ACC fitted? Of course, drivers can still set the system to leave a bigger gap, but then you aren’t getting the full benefit of the technology.

I’m still waiting for the day when you can drive you car on to the highway and not have to do a thing. Your car would simply travel along at a fixed speed until you reached your exit. Probably too boring for most people, but who it’s not much fun driving on a busy highway, especially if there are traffic jams.