Train-of-Cars

I'll start right off and say that the "Speed Sync Cruise" and the "Traffic Jam Cruise Control" Ideas (see links at above-right) have some similarities to this Idea, but certain aspects of what I want to describe were not well-presented, and so maybe this Idea might be different enough to be allowed to survive.

This device is an additional computer for a car, which connects to several other devices. One is a radar for measuring the distance to any vehicle in front; one is a connection to the car's cruise control system, including speedometer, one is a connection to the car's braking system, one is a sensor on the steering system, and one is a very low power radio transmitter at the tail of the car.

In operation, the Train-of-Cars computer first detects that the car is stopped. The assumption here is ALWAYS that the car is somewhere in a line of cars at a traffic light. The computer attempts to verify this by using the radar and listening to the transmitter of the vehicle in front. If not detected, the computer temporarily changes part of its assumption, to a mode in which it considers it is in the leading car of a lineup. The temporary assumption lasts until the car stops again, at which time another check is made for a preceding vehicle.

In the case where the car is first, the computer simply waits for the driver to accelerate, and transmits appropriate information about that acceleration through the radio in the rear. (An accurate speedometer, such as the Optical Speedometer Idea linked below, is required.) In the case where the car is not first, the computer listens for the data from the preceding car, and also passes that data on through the rear transmitter. With MUCH faster response time than a human, when the car in front accelerates, this computer also accelerates this car in perfect sync. Ditto for braking. The net effect is that with all the cars in the lineup passing data down the line, the WHOLE LINE accelerates in sync, just like a bunch of physically linked railroad cars. This bumper-to-bumper train of cars will have no significant gaps between them, and that automatically means that more will be able to get through a light than when the cars are under merely human control. Overall traffic flow is enhanced thereby.

Note that the drivers are NOT out of the loop here. They still have their own brake pedals, and if a brake is pressed (like when the traffic light turns yellow), then that car's computer immediately signals the change through the rear transmitter, allowing any/all trailing cars to slow safely, even as the leading cars start to pull away. Using the steering to pull out of the Train-of-Cars likewise signals any trailing cars to slow just a bit to ensure it happens safely. The only thing a driver in the middle of a Train-of-Cars can't do is accelerate. Only the first car can do that, and the driver of that car is NOT overruled by the computer, since the driver has a bigger picture of the traffic situation.

Note that because every driver still has control of the brakes, a Train-of-Cars situation is not dangerous when, for example, cars are leaving a parking area to get onto a road. Sure, the computer doesn't know that the car in front is not at a traffic light, but the DRIVER can see whether braking is required, or if the road is clear to allow the computer to let it accelerate with the car in front.