Motorists paying for trip time reliability in toll managed lanes - FL/I-95 Express featured as Fitch Ratings case study

April 4, 2012
By Peter Samuel

A 'special report' on toll managed lanes by Fitch Ratings finds that they maintain substantial traffic at uncongested times, apparently based on their promise of more predictability in trip times. To capture this idea the report is headlined "Paying for predictability: US Managed Lanes Projects."

But the report also presents data that managed lanes or (our preferred term) toll express  lanes (TELs) maintain some speed advantage over the free or general purpose lanes (GPLs) out of peak traffic times, and this may be another factor in their continued attractiveness to a portion of motorists throughout the day.

This at least is clearly a feature of the Fitch case study FL/I-95 Express

Usually toll express lanes (TELs) have been thought of as attracting patronage based solely on differences in average speeds at times of severe congestion, which suggests they have little attraction at times when there is generally free flow in the general purpose or untolled (GPLs) lanes alongside. But the Fitch report after looking at detailed quarter-hour by quarter-hour data across the day on FL/I-95 Express leads to the conclusion they have utility and appeal to motorists throughout the day and night.

2 TELs get 20% of the corridor traffic's 6 lanes off-peak


TEL shares of the total traffic - what the Fitch writer calls their 'capture rate' - are as you'd expect higher in traditional peak hours. They get 30% to 34% of the traffic in the busiest times. But they also get 20% most of the day, and only less than 20% very late at night and in the early morning hours.

On FL/I-95 in the segment with TELs there are two TE lanes and four GP lanes each direction, so volumes carried per lane are similar in congested periods.  The TELs just carry their volumes more efficiently thanks to the toll management of entering volumes.

A proportion of the traffic in the TELs is there for free by reason of being high occupancy and it's a pity they aren't separated out in the data. But it's likely to be small in number. FL/I-95 Express is HOV3 free/others tolled.

In the construction of the project one HOV lane each direction was converted to a TEL and a second TEL was a created each direction by restriping of lanes to 11ft from 12ft and by squeezing shoulder areas a little.  They went from 4 GPLs and one poorly utilized HOV lane to two TELs plus the same four GPLs.

Mike McDermott of Fitch, lead analyst on the managed lanes report says it would have been nice to have travel speeds by similar quarter hour intervals before the project opened for comparison, and average tolls corresponding to each quarter hour interval. Toll adjustments in response to traffic density are the means by which traffic flow in the toll express lanes is managed.

We simplified Fitch's simplified data

Our simplification of the Fitch data suggest that for all three segments southbound the TELs have a 13mph speed advantage (57mph vs 44mph) at the morning peak but still a 9mph advantage (65mph vs 56mph) around midday. The TELs' share of the traffic is 32% in the peak and 21% midday.

Fitch show separate data for three sections. There are intermediate entry points.

But most of the traffic uses multiple sections because there are no intermediate exits.

The rule is: "Once in the TELs you go to the end."

Of interest here is that the volume/capacity ratios in the highway while clearly higher in the peak (1.10) than at midday (0.82) they remain quite high throughout the day.

This is clearly not just a commuter road, but an all-round, daylong road serving many different purposes - probably the whole array of reasons people travel, trips to those 9-5 jobs to be sure, but also shopping, commercial, educational, recreational, social, short-distance, long-distance....

Vehicle types are a broad mix, though the TELs are reserved to 2-axle vehicles.

It is not clear quite why speeds remain so much higher throughout the day in the TELs but some possibilities are:

- faster drivers self-select and choose the TELs

- no trucks in the TELs is conducive to higher speeds

- less lane changing or weaving in the TELs

- a perception of more police speed enforcement in the GPLs (both are posted at 55mph which a majority exceed in relatively free flow conditions)

Greater efficiency of pricing

Fitch make the point that pricing is the means to efficient utilization:

"The capacity of transportation assets is not infinite and each additional vehicle beyond free flow capacity does impose an economic cost. Shaping the price based on usage is an economic concept conceived to alleviate, if not eliminate, the economic loss associated with congestion. This is analogous to the pricing strategy employed by parking garages, airlines, major sports leagues, and even some transit systems. Under this model, high-value trips pay for certainty, while lower value trips either take longer due to congested GPLs or occur in off-peak hours. In the end, the true cost of a trip is revealed.

"The primary goal of utilizing this strategy on a public highway is to encourage the most efficient use of a finite resource. Many urban highways operate at or above capacity during prime commuting hours, meaning their performance is poor. Given the urban nature of these facilities, adding more capacity can be costly because of right-of-way constraints. In addition, this may not be the most effective policy choice as the new capacity will encourage additional demand that the adjacent urban street network can not handle, resulting in congested conditions reappearing in the near future.

"Implementing a pricing framework should result in lower value trips diverting to public transportation, taking longer or occurring in off-peak periods when there is sufficient roadway capacity. Higher value trips will opt for the certainty of theTELs, for a price. This approach has been embraced by DOTs as evidenced by the plethora of projects that have come along over the last several years."

"More volatile" than typical tollroad

Fitch say that managed lane projects projects "have a robust traffic base to build from, but will prove more volatile than a typical toll road."

They don't provide any real evidence for the last point.

Typical toll roads are greenfields' affairs, located on the outskirts of urban areas and their traffic is highly dependent on population growth and outward housing development. Toll express lane projects by contrast are typically located deep inside an established urban area with a known and established customer base.

To be sure TELs are dependent on V/C ratios - the busyness of the adjacent GP lanes. And to a large extent they live off the congestion in the GP lanes.

But as the Fitch study shows they can offer a speed advantage and an attraction outside the peak congestion times, and offer a greater reliability or predictability of trip times. It is not clear to us they will be more volatile in traffic and revenue than typical new fringe tollroads.

Fitch study:

http://tollroadsnews.com/sites/default/files/FitchReport.pdf

http://www.95express.com/

reports on 95 Express:

http://www.sunguide.org/index.php/tmc_reports/TOLLROADSnews 2012-04-03

Further Reading


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