TDM 101: Intro to transportation demand management

Posted by Rachel Karitis on 11/9/17 3:37 PM

Let's talk TDM.

What is it?

Transportation Demand Management (TDM) is a term thrown around a lot in urban planning circles. If you're new to this world, you might have some questions. We're here to answer them in a multi-part blog series about TDM — what it is, why it matters, and some cities already using it.

TDM really is what it sounds like — a way of putting tools in place to help manage the demand for transportation that exists in a city. Rather than adding a new bikeshare station, it finds ways to encourage people to use the bikeshare station down the street.

TDM is about behavior change. It's a foundation for allowing all modes of transit to be equally used in unison, where people can determine the best option for a particular trip and make that choice with ease. When so many places make it easy for you to park, it finds ways to make it so you choose transit.

Okay, but give me some examples.

So what does this mean in practice? TDM can come in a lot of forms, like these:

Providing bike parking and changing facilities at work

Bike parking facility

There is a huge association between people whose offices make it easy for them to commute by bike and people who actually do it. A recent CityLab article discussed a study that found individuals whose work had cyclist showers, lockers, and bike parking were 4.86 times more likely to commute by bicycle. The biggest factor by far was the shower — and just 11 percent of the bike commuters in the study had this at their workplace.

Creating new developments near transit stations

You may have also heard of transit-oriented development, an increasingly popular practice in the TDM world. This creates less demand for parking right from the start, building up residential, commercial, and retail space near transit stations. This increases the likelihood that people will choose to use cars less frequently, and certainly not as their primary method of travel. It can also be an economic boon, as people are willing to pay more to live closer to work and play while increasing foot traffic for local businesses.

Employer subsidies for public transit and cash-out for parking

It's one thing to provide pre-tax subsidies for public transit to your employees — but the odds of them taking advantage of it if they also have the option to drive and park for free are very slim. A better option to offer would be disincentivizing driving at the same time, such as with a cash-out program. Here, employees get cold, hard bonus cash in place of a parking subsidy.

Washington, DC, has a bill on the docket that would require employers who provide free parking to additionally offer transit benefits or cash payments to workers who do not use the parking. UCLA urban planner Donald Shoup found that this could decrease single-occupancy vehicle commuters by 17 percent — a pretty significant difference.

Making information about transit options easily available

Man looking at TransitScreen in Brooklyn

Having people change their commutes can be difficult. There are multiple hurdles to overcome to convince people to shake up their habits. The first step is to fully inform them of all the options available to them — maybe they aren't aware there's a bikeshare station so close to the office, or perhaps they didn't realize just how often the bus comes during rush hour.

A display with all nearby transit options, like a TransitScreen, can give people the nudge they need to try something new. And having real-time transit predictions make the experience better — nobody likes waiting 20 minutes for a train that may never come — and in turn makes people more likely to try using transit in the future.

Building fewer parking spaces for new developments

The cost of parking spaces and the amount of time they are used far exceeds the weight they are given in our car-dependent society. There is simultaneously too much and yet seemingly not enough parking.

Several cities have begun reversing the scourge that is the minimum parking requirement, either completely removing them or at least reducing the number. You can find an ongoing map of which cities have done so over here on Strong Towns.

Allowing employees to work from home or work alternative hours

Commuting wastes time and energy and is terrible for the environment. So why do we still do it? Most companies don't have particularly liberal work-from-home or alternative-hours options, even though working from home is good for employee retention and and would save vehicle emissions. Alternative hours lowers congestion on the roads and on public transportation.

Now what?

Next time, we'll highlight some of our favorite cities and their TDM practices. One in particular you'd like to see? Let us know!

Topics: TDM, Real Estate