Monday, August 07, 2006

High Occupancy Post

About 5 years ago (just before the Olympics came to town), a massive I-15 construction project was completed that added new traffic lanes and especially a new carpool lane (more correctly known as the High Occupancy Vehicle or HOV lane). At the time, this was a major boon for travelers during rush hour who had more than one person in their vehicles, except when going southbound at around 10600 south (where the HOV lane ended and the merge was a real headache). This was improved recently with the extension of the HOV lane well into Utah County (I don’t know if the merge is still a problem that has just been transplanted to Orem because the lanes are so new, I avoid driving south during rush hour, and I don’t really care what happens in Utah County anyway).

The new policy allows drivers to purchase an express lane pass for $50 a month that will allow them to travel in the HOV lane (now redubbed the HOV/Toll lane) without any passengers in their car. At the same time, the lane is being repainted so that drivers are not allowed in or out of the lane except in certain areas (15 or so areas are to be included along the 38 miles of express lane, each at least a half mile long).

Naturally, this has enraged many people. They see the tolls as an elitist policy that some suggest will make less people use the HOV lane (which does defeat the purpose of the lane (which is to alleviate traffic congestion in general and encourage carpooling), but makes the lane better for those who continue to use it, so I’m not sure if they really understand their point). Many people complain about the entrance/exit rules, calling them ridiculous and difficult to use. Some of these people are just whining about change, and some have some good points to make. Without explicitly addressing anyone else’s arguments or complaints, I give my take on the situation.

First, allowing drivers to use the lane in exchange for paying a fee is a bad idea. I understand that the number of these passes will be limited, and they have to be renewed on a monthly basis, but this will increase congestion in the carpool lane during peak traffic times, reducing the benefit from using it. This reduces the benefit for carpoolers, making driving alone a more attractive option. Of all of the complaints that I hear about Utah drivers, the only one that I feel is truly justified is that we love having our own cars and are unwilling to take measures to reduce traffic congestion (e.g. carpooling or taking public transportation, the latter of which I feel is somewhat justified by the lack of effective public transit, which is in turn driven by the unwillingness to use it, etc.). Having a carpool lane was a good step towards encouraging us to think, if not green then at least cooperatively, about improving the Utah traffic situation, and allowing people to buy the same benefit without going through the trouble of taking on another rider undermines the system.

Second, the entrance and exit restrictions seem to be the most unpopular part of the new policy. In reality, it is an entirely different issue that is being introduced at the same time. Controlled access to carpool lanes is the standard policy in most places. This improves the flow of traffic in that lane because the cars don’t have to deal with merging except in specific, controlled areas. This will ultimately make the lane work better and it will make apprehending violators easier (if a vehicle is illegally in the HOV lane and sees a cop coming up, they can’t get out without facing a fine for illegal lane change and HOV violation).

The biggest problem with the controlled access at this point is that drivers don’t know where to get into our out of this lane. It would be good to introduce some signage to say what exits need to be accessed from each egress point so that drivers can plan ahead without first memorizing the entire freeway structure (a feat that many commuters can probably manage, but few others). If amazing feats of memory are required to effectively use the lane, then it will hurt the lane’s effectiveness (at giving incentive for carpooling), especially for visitors to the region.

It is worth noting that freeway driving during rush hour is a completely different experience than driving during other times. The purpose of an HOV lane is to improve traffic flow (at least for HOV drivers) during peak times. The new access restrictions will benefit this purpose, while allowing people to buy access to the lane will not. Since I am able to (and generally do) avoid driving the freeway during rush hour, I am far more interested in the likely effect that the new policies will have on driving during off-peak hours. I anticipate that the express lane passes will have minimal impact on traffic flow outside of rush hour. The lane access restrictions will make the HOV lane less attractive during those times, since the inevitable slow drivers in that lane will effectively slow you down for miles at a time instead of just until a gap opens up in the left hand traffic lane. I drove along the stretches of I-15 with a carpool lane many times as a single driver during light to moderate traffic and typically found that I could make at least as good of time in the other lanes as in the carpool lane. The only disadvantage was that I often had to change speed (although I didn’t have cruise control at the time, so it didn’t matter then). Since slow traffic in the HOV lane make it difficult to just get over there and hit cruise, this isn’t much of a loss.

I think it is worth noting that I have been working from several assumptions. I assume that people will choose the lane that they have permission to use that they anticipate will give them the best progress (this is basic economic theory, in that people will likely choose whatever will give them the most gain, although this actually breaks down often in traffic when people merge early into stopped lanes, but that’s another issue). I also assume that most users of the leftward lanes (including the HOV lane) will wish to go faster than the median traffic speed. At the same time, some people who are still traumatized by having unmarried parents will choose to travel in the HOV lane while going much slower than the surrounding traffic. While it is undeniable that they killed Kenny and that the road would be much better without them, they must be recognized just like a force of nature with regards to traffic flow.

I suppose that I could go into the morality of and possible justifications for introducing traffic policies as a way of increasing revenue. I don’t think that this express pass system will, by itself, raise enough money to consider it a fiscally good decision. The $100 fines for improper lane changes to and from the HOV lane has the potential to raise more money. (This raises the issue of using traffic violations as a source of revenue. I’m sure that the Fruit Heights City Council and I would likely find area to disagree on that one.)

I anticipate that restricting (physical) access to the HOV lane will be generally beneficial, especially if they can introduce some appropriate signage for it, and will typically be at worst a mild inconvenience. On the other hand, granting paid privileges to access that lane is unlikely to improve the overall traffic system in the long run, even if it does help alleviate congestion in the other lanes without adding undue congestion to the HOV lane.