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It occurred to me while sitting 9n traffic a month ago that I wished they would open up that other side. The one without any cars coming in the other direction. All that pavement was doing was getting wet and jettisoning “stormwater” that rainy morning, ruining the local stream anew. Of course traffic would move better with two extra lanes. The meager traffic moving in the opposite direction could easily fit in the one extra lane.

This is of course lunacy. We can’t just add and subtract lanes form directional traffic without a very clear message that everyone understands. I’ve only seen this in a few places, and only for a single reversible lane. The burden of traffic has to be dramatic for this switch to work. The first rules for motorized traffic were strict about lane enforcement and square turns at intersections.

In 1903, if America was going to survive the car, we had to accept some basic rules. Driving on the right had been in place for over a century. If a horse drawn again moving at 3 or 4 miles walking speed headed over to the left curb for a delivery few would complain as long as they watched their way. Driving on the wrong side of the road was not yet an allergy. It had to become one.

And that was almost two decades before the first traffic light.

Traffic is not the only culprit of wasteful overuse for the sake of safety. Transit is even worse. The commute share for transit is over 60%, while the commute share for traffic is around 20% Many buses and trains are going to be full in the morning, while at the same time their counterparts in the opposite direction are going to be nearly empty. Later, in the middle of the day, transit vehicles almost all run well below their break even capacity, to provide rides to the few who have irregular schedules. Commuter rail and commuter buses do not even bother with this. They send a fleet of transit into the city in the morning, discharge their passengers, and send the same fleet back out in the evening. Great for getting into work if you work downtown, terrible for anything else.


In traffic, the peak traffic (or rather, the 30th highest hourly volume in a typical year) is called the k-factor. This is the volume that traffic engineers try to design for, to manage congestion. This means that the ideally sized road is oversized for 8,736 hours hours of the year. Sometimes dangerously so. Of course traffic will move over 35 MPH* on the clear roads that result. Of course more stormwater will jettison into the local streams**. Of course, people won’t want to walk or bike anywhere near this torrent.


The solution is simple: build to enable as much traffic in one direction as the other, and build to enable round the clock travel needs. This is not what transit is generally built for, but heavily travelled arterials still exist with those kinds of schedules. Sth suburbs are actually better at this than the city, and a lot of commutes are switching from the 50s stereotype of the job in the city to the job in another suburb.

More than ever, the lanes and directions can’t reverse, but it doesn’t matter as much.

* The LS50 : the traffic speed that is lethal for 50% of the walkers or bikers that get hit by it
** Many unprotected as a matter of traffic safety and highway budgets