Stopping distance at red lights

[RocketDawg]

Originally Posted by Cloudy Dayz

You should be at least one car length back, but there is no harm in stopping farther back. No chain reaction crash has ever been caused by cars being too far apart. The same can not be said for people with herd mentality who always want to be right up on the bumper of the car in front of them.

The harm is it needlessly ties up traffic, especially if someone does that in fairly short turn lanes. Not talking right on the bumper - talking two, three, maybe more car lengths behind the car in front of them.

[RocketDawg]

Originally Posted by GrumpyCat

Don't make up things you clearly do not know. You get caught with your pants down.

A traffic light with sensors will never cycle unless it detects a vehicle. Alabama once had a law, many states still do, that a motorcycle stopped at a red traffic light for X seconds may proceed through the intersection if safe. The only need for this law was recognition the light will never cycle unless another large vehicle appeared.

Today, camera sensors are much better at detecting motorcycles than the buried inductive loops. Only about half the traffic lights have cameras.

The whole point of traffic light sensors is to not cycle, to not make vehicles stop for nonexistent cross traffic.

Negative. Call ALDOT or the city and ask.

[chucksnee]

.2.1 Pre-timed Control
Pre-timed control is ideally suited to closely spaced intersections where traffic volumes and patterns are consistent on a daily or day-of-week basis. Such conditions are often found in downtown areas. They are also better suited to intersections where three or fewer phases are needed (3). Pre-timed control has several advantages. For example, it can be used to provide efficient coordination with adjacent pre-timed signals, since both the start and end of green are predictable. Also, it does not require detectors, thus making its operation immune to problems associated with detector failure. Finally, it requires a minimum amount of training to set up and maintain. On the other hand, pre-timed control cannot compensate for unplanned fluctuations in traffic flows, and it tends to be inefficient at isolated intersections were traffic arrivals are random.

Modern traffic signal controllers do not explicitly support signal timing for pre-timed operation, because they are designed for actuated operation. Nevertheless, pre-timed operations can be achieved by specifying a maximum green setting that is equal to the desired pre-timed green interval and invoking the maximum vehicle recall parameter described below.

https://ops.fhwa.dot.gov/publication...4/chapter5.htm

[Cloudy Dayz]

Originally Posted by RocketDawg

The harm is it needlessly ties up traffic, especially if someone does that in fairly short turn lanes. Not talking right on the bumper - talking two, three, maybe more car lengths behind the car in front of them.

Short turn lanes is something that should be addressed with the local roads department. It's not something that should be compensated for by driving dangerously and stopping too close together. Most turn lanes are plenty long to accommodate leaving space between vehicles. If they are not, they should be lengthened.

[dwhisent]

Turning (left) north to Mem Pkwy service road from eastbound Governor's Dr immediately comes to mind. I have gotten stranded in the leftmost straight ahead lane because the left turn lanes are filled up and overflowing. There is a bridge there, so not much chance the turn lanes will be lengthened, would be expensive. Learned my lesson after one time, I always stay out of that lane when approaching that intersection.

[MisterEd51]

Originally Posted by dwhisent

Turning (left) north to Mem Pkwy service road from eastbound Governor's Dr immediately comes to mind. I have gotten stranded in the leftmost straight ahead lane because the left turn lanes are filled up and overflowing. There is a bridge there, so not much chance the turn lanes will be lengthened, would be expensive. Learned my lesson after one time, I always stay out of that lane when approaching that intersection.

If you are going to turn left at the next light by Checkers you probably want to be in the left lane. If the traffic is heavy and you are in the right lane you might not have enough time to change lanes if you don't.

[GrumpyCat]

Originally Posted by RocketDawg

Negative. Call ALDOT or the city and ask.

You know everything but have done nothing. Sit for 10 minutes at a lightly used intersection. The light will never cycle until it detects a vehicle. Never.

[harry chickpea]

Originally Posted by GrumpyCat

You know everything but have done nothing. Sit for 10 minutes at a lightly used intersection. The light will never cycle until it detects a vehicle. Never.

Nah. In Athens it will never cycle until it detects another vehicle in the cross street it can make sit at the light for 11 minutes.