Electronic payment allows more people to use the Express Lanes as-needed rather than having to pay a set $50-per-month fee. It also allows UDOT to better manage congestion in the Express Lanes to ensure that speeds stay around 55 mph for carpoolers. Charging solo drivers motivates drivers to carpool because tolls are highest during peak congestion when people most need the Express Lanes.

The Express Lanes are divided into four payment zones with overhead signs that show the price to travel in each zone. The new system is able to manage capacity in the lanes by using the supply-and-demand concept. An algorithm adjusts the price to drive in each zone based on traffic conditions with costs highest during peak traffic.

Readers at several locations along the Express Lanes detect in-vehicle Express Passes as they travel through the zones. After you exit the Express Lanes, your account will be charged the price in effect when you first entered each zone.

An Express Pass is a small radio frequency transponder that you mount to your windshield behind the rear-view mirror. Readers along the Express Lanes detect the Express Pass as you travel through the Express Lanes.

Each user will set up an online account with a $25 pre-paid balance and a credit card on file. Each use of the lanes will be deducted from your balance. Your credit card will be automatically charged $25 per Express Pass whenever each account balance goes below $10. Each $25 charge will show on your credit card statement. It takes three to four hours for a transaction to show up on your account.

Passes cost $8.75.

You can set up an account online or by calling 866-833-9824. You must purchase an Express Pass for $8.75 and deposit a minimum of $25 per transponder when you set up your account.

You can expect to receive your Express Pass five to seven business days after you open your account.

Pricing will range from 25 cents to $1 per zone depending on the level of traffic, with costs highest during peak traffic times.

The Utah Transportation Commission and the Utah State Legislature approved the minimum and maximum rates of 25 cents and $1. Rates are based on traffic analysis and similar programs in other states. The maximum rate may be adjusted with permission from the Utah Legislature and Transportation Commission depending on public demand.

As always, carpoolers, buses, C plate vehicles and motorcycles are the first priority in the Express Lanes and continue to use them without charge.

Yes. The Express Pass may easily be moved from one vehicle to another.

No. If you have an Express Pass in your vehicle but are carpooling, you can pull the slider down to the "OFF" position so that you are not charged. You do not need a pass if you only use the lanes when you carpool.

A carpool constitutes two or more people in a vehicle.

No. If you enter the Express Lane at the access point just before the next zone starts, you will not be charged for driving through that small part of the previous zone. For example, if you are driving northbound and enter the Express Lane at 9000 South, you will only be charged for the Salt Lake Zone. You will not be charged for the South Valley Zone.

Carpoolers, buses, motorcycles, emergency vehicles and C plate vehicles are the priority in the Express Lanes and may continue to use them without charge. Solo drivers may fill any remaining space for a fee.

Trailers and vehicles with a gross vehicle weight of more than 12,000 pounds are not allowed in the Express Lanes. Vehicles over 12,000 pounds are also not allowed in the adjacent passing lane.

Yes. The Express Lanes are for carpoolers first but until carpoolers fully use the lanes, solo drivers may pay a fee to use the remaining capacity. The new pricing system will allow UDOT to maintain speeds of around 55 mph to help motivate drivers to carpool.

More solo drivers will have the opportunity to use the Express Lanes when they need it most and to pay only when they use them. Whether you commute on I-15 regularly or are occasionally running late, you have the option to use the Express Lanes.

Higher speeds in the Express Lanes help drivers have a more predictable commute. Drivers save an average of 10 minutes when they drive the length of the Express Lane during peak traffic times. Maintaining higher speeds in the Express Lanes encourages carpooling, which is the first priority of the lanes.

The new system will ensure that the lanes carry their maximum capacity, freeing space in the general travel lanes while maintaining speeds of at least 55 mph. The Express Lanes carry twice as many people as general travel lanes during peak traffic times because of carpoolers.

Yes. Similar systems are functioning successfully in several other states including California, Florida, Minnesota, Washington, Texas, Colorado and Maryland and are under study in other locations.

Call the customer service center at 866-833-9824, deactivate your Express Pass and purchase a new pass. If your Express Pass is not working correctly due to equipment malfunction, it will be replaced without charge.

The Express Lanes span I-15 from 2300 North in Salt Lake City to Lehi Main Street and from Parrish Lane in Centerville to Layton Parkway.

By the end of 2012, the I-15 reconstruction project in Utah County (I-15 CORE) will extend the Express Lanes further south from Lehi Main Street to U.S. 6 in Spanish Fork. See a map of the Express Lanes.

UDOT's goal is to expand the Express Lanes from Ogden to Spanish Fork as funding allows. The I-15 reconstruction project in Utah County (I-15 CORE) will extend the Express Lanes further south from Lehi Main Street to U.S. 6 in Spanish Fork by the end of 2012. Click here to see a timeline of Express Lanes expansion.

UDOT's goal is to move the maximum amount of people through the corridor. The Express Lanes move more people with fewer vehicles because they carry carpoolers, but the lanes still have more capacity. By permitting solo drivers to purchase the remaining capacity UDOT can decrease the travel times for all drivers, including those in the general lanes.

Utah's Express Lanes are the longest in the country at approximately 40 miles long spanning from 2300 North in Salt Lake City to Lehi Main Street and from Parrish Lane in Centerville to Layton Parkway, when Layton construction is complete.

The Express Lanes are divided into four payment zones that vary in length:

• North Utah County Zone (Lehi Main Street to 14600 South) - 9 miles
• South Valley Zone (14600 South to 7200 South) - 9 miles
• Salt Lake Zone (7200 South to 2300 North) - 14 miles
• North Davis Zone (Parrish Lane to Layton Parkway) - 8 miles

When I-15 reconstruction in Utah County (I-15 CORE) is complete, the Express Lanes will extend further south to U.S. Highway 6 in Spanish Fork, making the lanes approximately 62 miles long.

UDOT uses tolls only to operate and maintain the lanes.

Express Lanes users may enter and exit the lanes at access points marked by white-dotted striping. Crossing the solid, double-white lines is illegal. An access point is located at each I-15 interchange. Users should exit the Express Lanes at the interchange before their exit. Signs along the Express Lanes indicate which access point to use to reach your exit.

The dedicated access points encourage people to plan ahead. It is unsafe to merge across five lanes of freeway traffic to reach an exit at the last minute. The striping was designed so that motorists have enough time to safely cross all of the lanes before they exit the freeway. Access points range from 3,000 to 9,000 feet long, giving room for users to enter and exit the lanes or pass a slow driver.

Other states that implemented similar access points to their Express Lanes found that speeds actually increased in their Express Lanes. Research showed that motorists in the Express Lanes drive slower when the traffic in the lane next to them is moving at a significantly slower pace. Drivers moving at freeway speeds in the Express Lanes are expecting that a vehicle in the congested, adjacent lane will pull out in front of them. Dedicated access points minimize this concern, giving Express Lane users confidence to travel at freeway speeds without the fear of someone pulling out in front of them.

It is illegal to cross the solid, double-white lines. Movements in and out of the Express Lanes are only allowed at access points with white-dotted striping.

Only carpools, motorcycles, buses, C plate vehicles, emergency vehicles and solo drivers with an Express Pass are eligible to use the Express Lanes.

Violators will be issued a citation with a fine of $90. UDOT and the Utah Highway Patrol (UHP) do not receive any of this money as it is dispersed to the local government agency where the infraction occurred per traditional means.

This new system is designed to make the Express Lanes easier to enforce. Lights behind the electronic signs show law enforcement the status of each Express Pass that travels under it.

• Green indicates the Express Pass was read and charged.
• Yellow indicates the pass wasn't read and law enforcement should check if the driver is carpooling.
• Blue indicates a negative balance on the account or the Express Pass was lost or stolen.

All UHP troopers enforce the Express Lane laws. In addition, the UHP dedicates two troopers and two enforcement vehicles to enforcing the Express Lane laws for each morning and afternoon commute. UDOT will continue to work with the Utah Highway Patrol to ensure the lanes are enforced in the best ways possible.

Follow the speed limit. The Express Lane is not a passing lane. The speed limit on I-15 is 65 mph and the majority of traffic is flowing at this speed. UDOT and the Utah Highway Patrol do not authorize vehicles to travel at speeds faster than the posted speed limit.

The Utah Highway Patrol watches specifically for motorists who are driving too slow, driving too fast, tailgating or exhibiting other Express Lane violations. This includes drivers in the general-purpose lanes who fail to allow drivers in the Express Lanes to merge.

Only Clean Fuel vehicles with a current C Decal (Clean Fuel-Clean Air decal) may use the Express Lanes for free. Under federal law, effective January 1, 2009, Clean Fuel vehicle owners must apply for a UDOT-issued permit to obtain a C Decal.

Beginning July 1, 2011, under House Bill 24, the Utah Department of Transportation (UDOT) will begin issuing Clean Fuel Vehicle decals to new applicants whose vehicles qualify as "Clean Fuel" vehicles under the U.S. Environmental Protection Agency (EPA) standards and federal regulations. The new decal program replaces the existing Clean Fuel license plate (C Plate) program for free access to the Express Lanes as a solo driver.

Under federal law, eligible Clean Fuel vehicles may operate for free in the Express Lanes as long as carpoolers are not negatively affected. On a yearly basis UDOT evaluates the impact of C Decal vehicles on carpooling in the Express Lanes to determine the number of permits to issue. If more applications are received than available permits, applicants will be selected on a random basis up to the number of permits allowed. Click here for more information.

In order for a Clean Fuel vehicle to travel in the Express Lanes without charge it must display a Clean Fuel Decal. If your vehicle qualifies, your Decal and a Clean Fuel permit will be mailed to you. When you receive your Decal, please follow the instructions included with the Decal to ensure it is properly displayed in your vehicle.

The Clean Fuel permit must be kept in your vehicle at all times. There is no cost to obtain a permit, however there is a fee of $10 for the C Decal. To apply for a Clean Fuel Decal fill out a C Decal Permit Application.

If you have a C Plate, you may keep the plate on your vehicle, but the C Plate license will no longer allow you to drive in the Express Lane as a solo driver.