Photo taken Friday, December 15 on I-66. Image by the author.

Two weeks ago, I-66 inside the Beltway transitioned from HOV lanes to HOT lanes, which allowed single-occupancy drivers to use the lanes throughout rush hour for a toll. At the end of the week, we were able to crunch the data VDOT provided on hourly rates, including usage and travel times. Here are nine takeaways.

1. Numbers can be turned many different ways

Figuring out what the average cost is can take you in many different directions. Last week we calculated the cost for a single driver to drive the entire 10 miles of HOT lanes at any point during the restricted hours by averaging the cost over 15 increments. This time-weighted average worked out to $7.43 for westbound travelers.

A December 7 VDOT press release listed the average westbound toll as only $3.80 for December 4. Data released by VDOT last week says 60 percent of the people traveling westbound paid more than $5 over the first four days. These VDOT dollar figures are calculated based on drivers getting off at all exits, rather than the entire length, and is weighted by the total number of drivers. Based on the parameters set, all of the numbers are right, but you can see how much the “average toll” can vary.

2. Carpoolers make up less than half of the users during restricted hours

The percentage of carpoolers traveling on I-66 throughout the first four days ranged between 30 to 45 percent. With such a higher percentage of single occupancy drivers you can only wonder how many of them were using the roads prior to last week when they were restricted to only HOV 2 vehicles.

3. Evening fares aren’t that bad

The Washington DC Metro is never associated with being inexpensive, but 40 percent of the people paid less than $5 when heading westbound in the afternoon. Previously we also noted that the formerly restricted time between 4 pm and 5 pm was actually cheaper than between 3 pm and 4 pm, which was previously open to all. About two-thirds paid less than $10 for the first four days for westbound trips.

Image by VDOT.

4. Morning fares are more expensive

Where two-thirds of the people pay less than $10 on their ride out, roughly two-thirds were paying more than $10 on their ride in. This is worth taking note of, because westbound had roughly 2,500 more vehicle trips per day.

The likely explanation is that evening peak trips are more spread out since people can leave work at different times. However, most workers have to be in at roughly the same time every morning, driving congestion and high toll prices.

5. High fares scare drivers away, like they're supposed to

Much was made of the $40 fare advertised on December 6th. On that day only 28 people were willing to pay that much to use the lanes. 39 people were willing to pay the peak of the peak fare of $34.50 on the first day when HOT lanes opened. Higher fares are used to relieve congestion, and it worked.

6. I-66 traffic speed stayed constant.

A year ago travel time during the morning rush hour varied from 10 minutes to more than 30 minutes. With the change, the lanes maintained a constant speed from 5 am through 9:30 am.

Image by VDOT.

Westbound travel time was also faster in comparison to the year before, and managed to stay constant over the rush hour.

Image by VDOT.

7. Eastbound local roads looked about the same.

Some drivers feared that the expanded tolling on I-66 east would push traffic to other local roads. It turns out eastbound roads, such as Route 50, 29, and 7, stayed about the same as far as average travel time.

Image by VDOT.

8. Westbound local roads stayed about the same too

Similar to eastbound traffic, some feared westbound traffic on local roads would also be majorly impacted. Instead, the published data shows it looks about the same again.

Image by VDOT.

9. No surprise that extended tolling lead to faster speeds

In the conversion from HOV to HOT lanes, VDOT expanded the restricted hours. These times before and after lead to much faster times as people avoided the tolls. Drops in travel time can be seen westbound from 3 pm to 4 pm and 6:30 pm to 7 pm.

Image by VDOT.

There will be more road work ahead for drivers. Two weeks ago, VDOT awarded an $85.7 million contract to add an additional lane along eastbound I-66 that will stretch from four miles from the Dulles Connector to Fairfax Drive (Route 237). The project includes ramp modification, bridge repair, and noise barriers.

Two weeks removed from the sticker shock of the peak-of-the-peak pricing, the numbers don’t look that scary. Local roads seem to be traveling at the same speed. Many westbound commuters are paying less than $5 for tolls. Speeds are staying constant. New projects to improve the roads are starting.

The I-66 HOT lanes are still in their infancy, but there are some promising signs after the first week.

Mike Grinnell has worked in the design and construction industry since 1998, and relocated to DC in 2001.  He has a BS in Building Construction from Auburn University and studied Economic Development in grad school at Virginia Tech.  Mike served two terms on the Potomac Yard Design Advisory Committee before moving to West Springfield with his wife and two daughters.