Managed Lanes, The Untolled Story

Ron Sifen

Tuesday, May 28th, 2019

As schools wind down and summer travel begins, commuters are thrilled to see weekday traffic improve on metro Atlanta streets and interstates. What many north metro motorists have begun to notice over the past year, however, is the overall, incremental improvement in their weekday commutes.

How is that happening?

According to the Georgia Department of Transportation, since the opening of the reversible express toll lanes alongside I-75 and I- 575 north of I-285, enough commuters are choosing to pay the tolls that it’s making an enormous difference to traffic flow in the general-purpose lanes.

The improvement is reflected in the data. The department compared the average traffic performance from January to February 2018 – before the toll lanes began operating – to January-February 2019. The express lanes opened in August 2018, and traffic direction is southbound in the morning and northbound in the afternoon and evening.

GDOT found that in 2018 at the peak of morning rush hour, the lowest average speed southbound in the general-purpose (regular) lanes was about 25 mph. In 2019 during the same peak period, the lowest average speed had increased to about 41 mph.

In 2018 the average morning speed southbound in the regular lanes was less than 60 mph for about nine hours, 10 minutes. In 2019, the speed was less than 60 mph for only about three hours, 5 minutes.  Part of the reason the morning’s southbound traffic is worse than northbound is that I-285 congestion backs up onto I-75 southbound, clogging traffic flow.

In 2018 southbound traffic averaged nearly six hours at speeds below 50 mph. In 2019, that had been reduced to a little over 90 minutes.

The average speed southbound was below 40 mph for about four hours in 2018. In 2019 – wait for it – the average speed was under 40 mph for approximately zero minutes.

In some ways, the data for northbound traffic regular lanes during the afternoon and evening are less dramatic, and in other ways more dramatic.

In 2018 the lowest average northbound speed during afternoon rush hour in the general-purpose lanes was about 26 mph; in 2019 it was about 53 mph.

In 2018 the average speed was under 60 mph for about five hours, 15 minutes per day. In 2019, it was about two hours, 45 minutes. Motorists endured average speeds under 50 mph for almost four hours in 2018; in 2019, the average speed was under 50 mph for zero minutes.

In 2018 the average speed was under 40 mph for more than 2.5 hours. This year, even at the peak of rush hour on typical days, the average speed never gets down even close to 40 mph.

No matter how you look at the data, in both the morning and the afternoon, average speed is dramatically faster in the regular lanes and the time spent in rush-hour congestion is dramatically reduced since the toll lanes opened.

A recent transit study, the Top End I-285 Transit Feasibility Study, recommended Bus Rapid Transit operating on new express lanes on the northern part of the Perimeter – two in each direction. Expanding that approach all the way down to I-20 makes it a transit option that could cost-effectively contribute to further reducing traffic congestion. Already on I-75 and I-575, the Express buses travel free in the reversible toll lanes, and passengers are experiencing a 15-minute improvement in travel time over using the general-purpose lanes on the interstate.

The express lanes have been a cost-effective project for taxpayers. The total cost of about $836 million will be reimbursed by the tolls over time, and the excess will be used to maintain and operate the lanes. Those who choose to use the lanes are paying, while those in the regular lanes are benefiting as well.

The I-75/575 Express Lanes are proving to be good for commuters and for taxpayers and, going forward, the expansion of toll lanes into a metrowide network will continue to improve mobility, relieve congestion and enhance transit options.