Bike box rationales

On another Web page, I have discussed the features and operational characteristics of so-called “bike boxes”, in which bicyclists wait for traffic signals ahead of the stop line for motor traffic. I recommend that page as background information for this discussion.

In this posting, I will discuss rationales advanced for the installation of bike boxes.

There are two principal rationales for a bike box, one of which I regard as valid but which might better be served by a different implementation. The other rationale, I find very distressing.

The first rationale is to accommodate a high volume of bicycle traffic, where bicyclists might have to wait through multiple signal cycles behind motor traffic, or else might filter forward and then not have room to wait. I recommend that bicyclists wait behind the first motor vehicle, so as not to be caught on the light change, and to negotiate with the driver of the second vehicle in line. That places the bicyclist in the exhaust of the first vehicle, but that’s better than risking a right hook collision. The exhaust problem has become far less serious in countries which have mandated pollution control on motor vehicles. But — there’s only so much room behind the first vehicle for a couple of bicyclists. A bike box behind the first vehicle would formalize that option, but unfortunately, the length of vehicles varies.

A bike box is advantageous in terms of bicyclists’ travel time when going straight through the intersection, if it facilitates filtering forward past stopped traffic — though, on the other hand, it increases motorists’ travel time. The bike box makes no significant difference in a bicyclist’s through travel time when the bicyclist arrives on the green.

But a bicyclist can get caught at the right side of the roadway when approaching the bike box, and the light turns green. Merging into the flow to go straight, or make a vehicular left-turn, is more advantageous unless traffic is very congested. (And that’s one reason among others that use of a bike lane should not be mandatory!)

The other rationale for a bike box is to encourage more people to ride bicycles by increasing comfort. I find this rationale very scary when the supposedly comfortable facility includes a deathtrap. I call this the “Pied Piper” approach to bicycle planning. It involves some convoluted thinking — bicyclists fear motorists, so, build facilities which appear less scary to the bicyclists.

A bike box with a pre-green signal interval (red and yellow in European practice) provides a warning for a bicyclist not to overtake and swerve in front of the first motor vehicle waiting at the intersection as the light turns green. He/she can still get stuck waiting for through traffic to clear, and the signal to turn red, then green again, if the intention using the bike box was to prepare a left turn (as with a Vancouver, BC bike box and some in New York City) or to cross to the other side of a one-way street (as with a bike box in Eugene, Oregon).

Motorists waiting behind a bike box without the pre-green are expected to look for bicyclists in their right rear-view mirror while also scanning the intersection ahead. That increases the likelihood of mistakes in both tasks, but also, the right rear-view mirror doesn’t provide complete coverage of the area where a bicyclist may be, particularly for the driver of a truck or bus with a high cab and a hood. If the motorist doesn’t look into the mirror at the right time, the bicyclist may have passed outside the field of view seen in the mirror. That is the rationale for additional mirrors, beepers, bicyclist-presence actuated flashers etc. that have been proposed to warn motorists of bicyclists overtaking on the right, and warn bicyclists of motorists preparing to turn right — none of which measures have been implemented in practice and all of which are technological solutions, with the attendant problems of implementation rollout and reliability.

So: what to recommend? here’s what I suggest. Never overtake a long truck or bus with less than 5 feet of clearance to its side, not even in a bike lane. Preferably, overtake on the left or move forward in line with other traffic, but in a traffic jam, you may filter forward *slowly* in a bike lane. Be aware of thehazard of car doors opening from either side, pedestrians stepping out form in front of tall vehicles, etc. Never swerve across in front of a vehicle unless you can be entirely sure that it will not start to move. Make eye contact with the driver, signal your intentions. If you can’t see the driver in a high-cab vehicle, just don’t swerve left. Pulling into line behind a vehicle that is waiting for a traffic signal or stop sign is reasonably safe if you obey these precautions. Swerving across in front of a vehicle waiting first in line, even with a bike box, is only safe if you can be sure that the traffic signal is not about to change.

Alternatives to the bike box?, For less-skillful bicyclists in urban areas, I favor the bicycle boulevard concept, in which bicyclists and motorists share a roadway according to the normal vehicular rules of the road, on a street with low traffic volume — typically, a residential street paralleling an arterial, using diverters and small traffic circles to keep down the volume and speed of motor traffic. This approach avoids the problems with attempting to accommodate conflicting movements with special facilities on a street that also carries heavy motor traffic. There are tradeoffs, to be sure: the bicycle boulevard isn’t a main street, so it may not provide such a direct route between as many trip endpoints — and unless bicycle transportation is taken very seriously, the bicycle boulevard may not have as favorable signalization as a main street. I have seen and ridden bicycle boulevards in Berkeley and Eugene, and they do seem to work rather well in those cities. No, I don’t have use or crash data, only my personal observation.

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