Research

We’ve written about our concerns with the traffic congestion autonomous vehicles could cause.

Now Mark McDowell breaks it down over at Eno’s blog: “It is estimated that for every 5 percent decrease in automobile ownership, ‘vehicle miles traveled’ will increase 10 percent. Offsetting that is the estimate that AVs should dramatically increase street and highway capacity. Should planners not be asking what the net affect would be on which corridors?”

Affects on urban form
It is estimated that one shared AV could replace 11 automobiles. The implications for parking requirements and thus urban and suburban form are obvious. Or, if the majority of customers arrive in driverless vehicles, then do we need on-street parking? Do curbs become just a nuisance?

Affects on suburban form: no end to sprawl
With increased mobility producing higher VMT, there is no reason to believe sprawl will cease. The economics of suburban real estate combined with lower mobility costs due to not owning a car, should encourage continued robust suburban growth.

Affect on transit: More service for less money
AVs will scramble our current notions of transit, particularly in low density, suburban settings. Today a 40-passenger bus costs about $300,000. Many fewer than 10 AV’s, on average, would be needed to equal the capacity of one bus – and probably at significantly lower cost. It would therefore make prima fascia sense in limited demand settings to transition from buses to AVs and offer door-to-door service, faster transit time, and greater comfort than a bus. Additionally since AVs are perfectly suited to taking small numbers of people to diverse destinations, a transit agency untethered from buses and rails should see a huge growth in demand from former automobile owners. Except that the private sector may provide the service first.

Affect on paratransit
The driverless vehicle would greatly enhance mobility for the disabled, especially if concepts such as the one below are developed further.

Affect on Inter-City Transportation
AVs have implications for intercity transportation as well. Imagine vehicles that will pickup passengers in front of their house, head to the appropriate interstate (AVs only of course) and insert themselves into a passing platoon of vehicles travelling at say 115 mph. Given such capabilities, developing AV-exclusive roadways might be more cost effective than building “higher” speed (maximum 115 mph) rail. Certainly they would be more convenient. Why would anyone get in an AV just to go to the train station when they could get to their destination faster and possibly less expensively using an AV all the way? Perhaps it would be wiser for state DOTs think about exclusive throughways for autonomous vehicles rather than plan rail projects that are 10 or 20 years out.

Whither Planning?
Policy makers are not anticipating, and certainly not planning for, the secondary affects of AVs. For example, metropolitan planning organizations (MPOs) are required by the federal government to prepare a long-range transportation plan (LRTP) that looks forward 20 to 30 years. This is within the time frame when a substantial portion of the automobile fleet is likely to consist of fully autonomous vehicles. I doubt the current LRTP of any MPO takes this into account. As a consequence, we are designing infrastructure for yesterday instead of tomorrow. Since it can take 15 years between inception and completion of a federally funded project it is entirely possible—given the rapid pace of AV technology development—that by the time a major project designed today is completed, it will be inappropriate, if not obsolete.

Read the complete article at Home – The Eno Center for Transportation