Two years after their Utah debut, carpool lanes remain a relatively foreign concept to some motorists.
But the Utah Department of Transportation says the 17 miles of high-occupancy vehicle lanes on I-15 in Salt Lake County are "currently meeting expectations" and will become even more valuable in the future.
"Our HOV lanes represent one of our best methods for meeting increasing demand," said UDOT deputy director Carlos Braceras.
"This is really the type of thing that makes our system better so that we can meet that future capacity."
Braceras admits there are some concerns about the HOV lanes — some people still use them illegally, they are somewhat underutilized, they are available on only one freeway and don't cover that much ground.
But the Utah Highway Patrol has been diligent in enforcing proper carpool-lane use, violations appear to be down and the lanes are gradually receiving more use, Braceras said.
And HOV lanes will become more integral to decreasing congestion in the future when they likely will stretch north into Davis County, south into Utah County and perhaps east and west in Salt Lake County.
"You really can't put in a light rail line and not have any connections to it," Braceras said by way of comparison. "We need to give I-15 and the HOV lanes time to mature to reach their full benefit."
While not directly under attack, I-15's HOV lanes will draw more scrutiny over the next two years as Dec. 31, 2005, nears. That's the expiration date for state legislation that permits clean-fuel vehicles to use the carpool lanes.
The Utah Legislature may conduct a full review of the HOV system next year in preparation for either renewing that legislation or allowing it to expire.
Utah would run into stumbling blocks with the Federal Highway Administration and air-pollution standards if it ever tried to do away with carpool lanes altogether. And that isn't likely to happen.
But the state's HOV law could be altered, and lawmakers already have hinted at one particular change they might want to explore.
During a recent meeting of the Transportation Interim Committee, state lawmakers discussed the idea of allowing single-occupant vehicles to use the HOV lanes by purchasing a permit. The practice, known as "value pricing," is popular in California.
That could involve a sophisticated monitoring system that would detect vehicles with special permits. Or, as Rep. Jim Ferrin, R-Orem, suggested, motorists could simply buy an annual sticker that would be affixed to their car.
But in addition to requiring federal approval, Braceras said allowing value pricing in I-15's HOV lanes would be a "significant operational change" for UDOT. And value pricing, he said, could detract from what now makes the carpool lanes attractive — fewer cars are in them, so it takes less time to get somewhere.
Braceras said a recent UDOT study shows the HOV lanes on I-15 are becoming increasingly popular during the evening commute, which is typically longer and more congested than the morning commute.
In the peak hour each morning, I-15's four northbound general-purpose lanes are each carrying 1,500 vehicles per hour while the carpool lane is carrying 350 vehicles per hour.
But vehicles in the carpool lane have an average of 2.7 occupants, compared to an average of 1.1 per vehicle in the general-purpose lane, he said.
So, the HOV lanes are much more efficient at transporting people. And that's significant, Braceras said, because demand is growing much more rapidly than UDOT can possibly increase the capacity of Utah's highways.
All these observations lead Braceras and his UDOT colleagues to conclude there is only one thing that should be done with the HOV lanes and the way they currently function — absolutely nothing.
E-mail: zman@desnews.com