What Drives Us episode

Read the Stoplights

4 Jun , 2016  

– Tony Schaefer

There is no denying that one of the greatest hindrances to hypermiling is the stoplight. They force you to ruin a perfectly good head of steam and then force you to make the car accelerate from a dead stop. As mentioned in another article, it would be best to use the brakes as little as possible by timing the stoplights such that stopping is not required. Some suggestions were provided in that article but they only scratched the surface. This article aims to dig deeper and provide some suggestions and insight into dealing with various types of stoplight intersections.

NOTE: These examples are based on my experience with stoplights. There are some places were the order of progression is different from those given below. For example, in some locations, left-turn lights precede straight whereas in other places, straight precedes turns. If the lights are different where you live, then please try to work out the differences as they apply.

The Standard Stoplight

Let’s start with an easy one.
1. Easy Stoplight

In this case, the stoplight is green and you can continue through it. But is it really that easy? How long has the light been green? If you know your route, you have a general idea how long before this light changes to yellow and then red.

If you just saw this light turn green, take your time. However, if you feel this light is “stale” or have no idea when it might change, then it might be best to accelerate through it. Sometimes it is better to burn a little gasoline speeding through a light than take the massive hit brought on by dead-stop acceleration.

Red Means Stop

Here is a typical red light.

2. Red LIghts - Yellow on the Sides

Most people would look at this and see that the light is red and therefore, you will be required to stop. A hypermiler, on the other hand, looks at the side lights and sees they are yellow. With some luck and good timing, you should be able to coast up to the light just after it turns green. Always watch the side street for people running the yellow or red.

Bonus Points: If you are turning left at this intersection, you are most likely going to stop. Many left turn lanes are triggered only when there is a car waiting. Since this scene does not show a car, there is a good chance the “straight” light will change green while the left-turn light will stay red. If you have the option, consider continuing straight and trying your luck with the next light.

Left Turn Light

Notice that the left turn light is green and there is a car waiting to go straight.

3. Green Lights with Green Turn Light

If you are going straight through the intersection, there is no need to rush. The left-turn light is delaying the oncoming traffic. Even after the left-turn light changes to yellow and red, the oncoming traffic will have their entire turn during which time you will have the green light.

This is also important when there is a line of cars in front of you. Perhaps only ten cars can get through the light normally; when the left-turn light extends the straight light, perhaps fifteen or twenty.

Car Turning Left

Notice that the oncoming car is going straight while the car in front of you is turning left.

5. Red Lights - Car Turning Left

In a very real way, this situation is about ten seconds prior to the previous image. The car in front of you will trigger the left-turn light when your light turns green. The oncoming car is not in the left-turn lane and will sit there. You will have an extended green light to proceed at whatever rate you desire.

Red Light with an Oncoming Car Turning Left

Notice the yellow lights on the sides and the oncoming car in the left-turn lane.

4. Red Lights - Yellow on the Sides

As you approach this intersection, there’s simply not much you can do. The oncoming car is going to get the left-turn light and you will have an extended red.

The Killer

Yellow lights.

6. Yellow Lights - You're turning Right

This is the situation no one likes to see. Yellow lights as you approach the intersection. In this situation, you will stop.

Bonus points: Notice this image has the addition of a right-turn lane. If the white car is turning left, there is a strong chance you will get a right-turn light. If this is the case – and you will know this because you have memorized your route – then you should be able to slow enough to wait for the turn light and then zip through the intersection. However, you must look at the white car to make sure it is in the left turn lane. Additionally, be on the lookout for cars in front of you who do not know there is a right-turn light; they will probably come to a complete stop.

Two Lanes, Two lines of Cars, No Right Turn Light

No picture for this one. As much as I preach staying in the right lane unless passing, this is the situation in which I always get into the left lane. The reason is simple: there’s a high probability at least one of the cars in the right lane is going to turn right. This means cars will lurch forward to go through the intersection but have to slam on their brakes when someone slows to make the turn. On the contrary, every car in the left lane is going straight unless there’s a left-turn lane and some of the cars shear off to the left. Double-bonus!

Summary

I’ve presented some intersection and stoplight possibilities. There are, of course, many more. But hopefully, with these examples, you have seen how important it is to identify the condition of other lights, the position of other cars, and the conditions they might bring about. When you start to notice these things and reacting appropriately, the number of complete stops will dwindle and overall mileage will increase.

 

Table of Contents

 

, , , , , , , ,