Road rants

It is time for another edition of Road Rants where, after going on a road trip where I have time to think of these things, I note the driving practices I see that annoy me and make suggestions for improvement. The previous rants were here, here, and here.

Turning on lights

On the highway several times I came across a sign saying that there was construction ahead and to turn on the headlights. In each case there were about six or seven cars ahead of me, not one of whom bothered to turn on their lights. On the other hand, when there was a sign saying that we were about to enter a tunnel and to turn on the lights, everyone did so, though some only after entering the tunnel.

Why is this? I suspect that most people do not realize that turning on the lights serves two purposes. It helps you see better but it also helps others see you better. Most people only think about the first. As long as they can see without turning on their lights (which is the case in daytime), they see no point in turning on their lights. It does not occur to them that it helps the construction workers on the road see cars earlier and better and take evasive action if necessary.

This reluctance to turn on headlights is annoying and dangerous when driving in heavy rain or snow where the visibility is poor. Turning on your headlights doesn’t enable you to see further, so some drivers don’t turn them on, not realizing that by keeping them off, they become largely invisible to others on the road. Very often you will find cars suddenly emerge from the gloom without warning because they did not have their lights on. I wish Ohio would enact and enforce a law that some states have that says that when your wipers are on, your lights must also be on.

Hogging the passing lane

Another practice that puzzles me is that of those drivers who get onto the passing lane of the highway and stay there. Apart from the fact that it is against the law, what are they thinking? People who do that in moderate levels of traffic can block traffic behind them for quite a distance. Surely they must notice that other drivers drop back into the slow lane after passing? Surely they must wonder why they do that? Or are they so oblivious to others that they think that as long as they are going close to the speed limit, it does not matter which lane they are in? I used to think that the people who did this were the stereotypical old geezers but on my last trip I noticed that the culprits were middle-aged and even young drivers.


Recently cities and states have been increasing the use of cameras to detect people who go through red lights or speed in built up areas or construction zones. This has generated a remarkable level of angry opposition with citizen petitions seeking to outlaw the practice.

I am a little puzzled by this reaction. While I am usually concerned by invasions of privacy, this does not seem to me to be such a violation. It seeks to deter dangerous driving practices and nab those who do so without the wastefulness of having police idling for hours in hidden spots, when they could be doing far more useful things like preventing and solving more serious crimes. So what is the problem with these cameras? Do people want the freedom to drive dangerously? It is true that some communities are using these devices as a means for increasing revenue but that does not seem to me to be a disqualifying factor.

Highway merging (again!)

Some time ago, I suggested that when the number of lanes is reduced on a highway (which usually creates a bottleneck), that it was most efficient if traffic in both lanes went up to the merge point, the so-called ‘late merge’ policy, rather than merging much earlier which is what traffic etiquette seems to require.

In response to other points of view, I modified that stance to say that perhaps the most efficient way to merge was if both lanes could maintain speed while doing so, which suggested an ‘early merge’ policy, before traffic congestion built up enough to prevent merging while maintaining speed.

It now turns out (thanks to a subsequent comment on the first post by Chandra, who is both a traffic engineer and an old school friend of mine who stumbled on my post while doing some research on this topic) that a study finds that during congested times, the late merge is best after all, while at other times the regular merge rules should be followed.

A new book Traffic by Tom Vanderbilt cites other research that supports the late merging policy.

Among Vanderbilt’s findings is the discovery that “late merging” may actually cause traffic to move more quickly, contrary to popular belief. When a sign warns that the lane will end in a given distance, standard driving etiquette causes many to move over as promptly as possible. However, if everyone were to merge at a single point when the lane ends, the road would get maximal usage and lane changes would become more orderly. The result would be traffic that moves 15% faster than current behavior allows.

“If people were told exactly to not leave the lane that was closing until the very point it actually did close, and then we did a nice alternating merge — it would be faster,” says Vanderbilt. “Another benefit would be the queue of vehicles stretching back from the construction site would be smaller.”

More traffic circles please!

Vanderbilt’s book also supports my feeling, based on my driving experience in Australia and New Zealand where traffic circles (or ’roundabouts’) are ubiquitous, that we should have more traffic circles here.

Vanderbilt also argues that round-abouts may be safer than traditional stoplight intersections. Though traffic circles may seem confusing, they have fewer “conflict points,” places where cars can physically hit an object or person. Intersections have 32 of these conflict points, where round-abouts only have 16. The round-about is particularly safe because it completely eliminates the left-turn, one of the most dangerous driving maneuvers.

POST SCRIPT: Common food myths

Following up on my recent series on food, I was sent this interesting article on common food myths (Thanks to Ashali).


  1. says

    At the core, I don’t really oppose red light and speed cameras. As a matter of how those systems have been implemented, however, I have very strong objections (I don’t know what the problems of others are, on the whole, but I know many who share these same concerns).

    Most cameras (in the U.S. at least) are operated by private vendors, who get a significant percentage of each ticket issued. This, in turn causes them to lobby legislators to reduce things like yellow-light times on monitored intersections, sometimes to bizarrely ridiculous levels (e.g. 2.9 seconds on a 45mph road or something similar). This makes these intersections far more dangerous, as people are now encouraged to stop short rather than risk running the intersection. Many of these intersections have shown significant increases in the number of rear-end collisions, thus nullifying the safety argument involved.

  2. says

    Just as Jim said, I keep reading that the big problem with stoplight cameras is that city officials exchange safety for revenue by shortening yellow-light times. And according to a BBC article the speed cameras can be quite inaccurate, though they’re a bit light on the physics.

    Now why Mississippi is banning red-light cameras; here’s why.

    Also, I’ve heard a few anecdotes of the red-light cameras nabbing Clevelanders who merely stopped a bit over the white line yet did not actually proceed into the intersection. Sure, that’s sloppy driving (exception: black ice), but hardly a dangerous offense worth a $100+ fine.

  3. says

    I would have thought that the length of the yellow lights would be determined by some formula depending on the speed. Are they really set arbitrarily?

  4. says

    It’s my understanding that the USDOT publishes guidelines for states to use that are formula-based, but they are strictly recommendations. States, and in some cases, individual municipalities have a wide latitude to arbitrarily set yellow light timing.

    There have also been cases where individual municipalities have violated state laws by shaving .1 or .2 seconds off of a yellow light time (with significant revenue increases). Some of them have been caught by vigilant individuals and have been forced to correct their behavior, but after many citations were issued that were paid off without question.

    I get most of this information from a blog I follow called The Newspaper: A Journal of the Politics of Driving.

  5. Josh Friedman says

    Ahh, the late merge debate. I recently had this discussion with a friend after seeing signs on the PA Turnpike telling me to merge at the point of lane closure.

    Most of the studies we found said the benefit of the late merge was only statically significant when the lane closure was from 3 lanes to 1, or when more than 20% of the traffic was trucks.

    One thing I have always noticed is that trucks like to prevent late merging by driving halfway in the closing lane to prevent cars from passing them up to the merge point. I’m not sure how or why that practice started…

  6. says

    Josh: I’d guess it’s because truckers don’t like being passed on the right. Just due to mirror configuration and such I’d always heard it’s harder for them to see smaller vehicles on that side. The blind spot is larger.

    So I assume the behavior is to prevent them from running cars off the road at the end of the closing lane, should the speeds not work out for merging. Of course, the driver of the car would still have to be dumb enough not to brake in time. But I’d plenty of other drivers try to race ahead to beat the truck to the merge point, which isn’t safe either.

    Again, no numbers to back this up, but if I drove a truck I wouldn’t be keen on accidentally running cars off the road or having them cut me off.

  7. Ravi says

    In addition to the yellow light shortening problems mentioned above, another problem with red light cameras is that the system is automated top to bottom, from the point the camera nabs a license plate to the ticket that arrives in the mail. Anything that requires human intervention makes the system less profitable and thus is not used. As a result, it fraught with errors.

    In Chicago, I got a $200 ticket from a red light camera for turning right on a red after stopping at the line, which I was allowed to do. It wasted about 10 hours of my time altogether to get it discharged. The ticketing system also is fooled if you stop a foot or two past the white line (sometimes the location of the white line is even miscalibrated). So people get tickets in the mail for “running a red light” at 2mph and stopping a foot over the line; something that no reasonable policeman would ticket for.

    The net effect of this is that drivers (myself included) tend to slam brakes on yellow lights, and that mostly just increases rear end collisions.

    If the real desire is for increased safety, an extra second of yellow light time, followed by an extra two seconds where all lights in the intersection are red is one of the most effective ways to accomplish that.

  8. says

    It seems like the issues that cause angst concerning cameras have technological fixes to avoid the kinds of heavy penalties for minor infractions that Ravi describes. Unless, of course, cities want to use these devices to increase revenues rather than reduce accidents, which, as Josh suggests, seems to be the widespread suspicion…

  9. James Chang says

    The yellow-light period is roughly 3 seconds, and I know that certain state authorities are trying to shorten it just to increase the possibility of additional traffic fines. Honestly, red-light cameras are there to raise revenue for the city and/or town, not to increase traffic safety.

    If there was a sign telling drivers they are entering a red-light camera enforcement zone, then they would pay close attention to stopping at a red light instead of trying to gun out the engine in order to beat it. That’s safety.

  10. says

    I’d like to suggest analysing cellular phone data
    in addition to monitoring people who go through red lights via cams. We’ve done several experiments and found out that the last thing that riski drivers do is shuting their cell phones down. Why they are riski? Peeple don’t want to think. It’s too complex.

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