Road trips take longer in rush hour, we all “get” that. And we all know that traffic isn’t “average” every day; it varies a lot.
When you really need to be somewhere at a specific time — whether it’s a family dinner, a meeting, picking up a child at daycare, or a doctor appointment — you have to plan for the possibility of an even longer trip.
As bad as Atlanta’s traffic jams are, it’s even more frustrating when you can’t depend on how bad the traffic will be.
Texas A&M Transportation Institute’s 2012 Urban Mobility Report includes a measure of this frustrating “extra” extra travel time — the amount of time you have to allow above the regular travel time.
Our dataset from INRIX (a leading private-sector provider of travel-time information for travelers and shippers) catalogs many speeds for each piece of road during the year. These have been analyzed to identify the longest travel times — the ones that you have to plan around.
The planning time index (PTI) identifies the extra time that should be allowed to arrive on-time for a trip 19 times out of 20, meaning you should be late for work only one day out of the 20 workdays per month). So if your boss will let you be late to work one day a month, this measure gives you an idea of how much time you should allow to get to work. If the PTI for your trip is 3.00, that tells you to plan 60 minutes for a trip that takes 20 minutes when there are few other cars on the road (20 minutes x 3 = 60 minutes) to ensure you are on-time.
Our estimates show that while Atlanta’s freeways have the 7th-highest congestion ranking in the U.S., they are only the 21st most unreliable. So, the roads are very congested, but travel times are more reliable than many other congested regions.
Not exactly great news, but it shows what is possible when there is a focus on improving performance.
How does Atlanta improve? We recommend several strategies that focus on “more of everything.” Atlanta’s population growth will require more roads and transit.
Those systems also have to be efficiently operated; the Georgia DOT NaviGAtor system plays a key role in quickly clearing crashes and communicating problems.
Travel alternatives — options like flexible work hours and teleworking — will also play a key role for those who have the ability to do their jobs from anywhere. And developments that allow people to live, shop and work without auto commuting also offer attractive options for some city residents.
But, in all cases, the solutions need to work together to provide an interconnected network of mobility services that allow metro Atlanta residents to get to where they want to be in a predictable, and not overly long, time.
(More information about the TTI report at mobility.tamu.edu/ums)
