HOT lanes

High Occupancy Toll lanes are a free-market solution to traffic congestion. Unlike a conventional toll road where all of the users pay an established toll rate, HOT lanes are designated lanes on an existing road where variable tolls are posted. If a user is willing to pay the toll, he may use the lane. Otherwise, the user has the choice of using the untolled lanes which are more congested. As more cars opt to use the HOT lane, a computer automatically raises the toll to discourage overuse, thereby keeping traffic in the lane flowing at the designed speed.

HOT lanes differ from HOV lanes, which are available only to car pools having a designated minimum number of passengers. Car pools are allowed to use the HOT lanes without paying a toll, provided that the car is carrying a special RFID transponder. Unlike HOV lanes which are typically financed from gasoline tax revenues, HOT lane construction is financed from the toll revenues.

Toll collection

Traditional toll roads required all users to stop and pay at a booth before continuing travel. Modern toll roads use transponders and radio frequency identification (RFID) to keep track of usage. Each transponder is linked to a financial account which draws money from the user's credit card. This highly automated process can greatly reduce labor costs, but creates the possibility for misunderstanding and noncompliance. The tolling points have both RFID antennas and video cameras. When a vehicle drives under the toll gate, the transponder on the car sends an identifying number to the antennas. If the antennas do not receive a signal, photos from the camera are automatically saved with the hope that a license plate number is visible. To deter scofflaws, the drivers who do not have transponders are billed an amount greater than the otherwise applicable toll. For example, in one case in Northern Virginia, a drive used an HOT lane eleven times, which would have caused his account to be charged $11 in tolls. The driver had failed to properly set up auto-renewal on her account, so her transponder did not work. She paid the $11 in tolls, but the private company running the HOT lanes sued her for over $10,000 in additional charges and penalites. Some HOT projects specify that if car pool usage exceeds a specified level, the government must pay the tolls for the excess car pools.

Examples

• I-495 Express - four lanes on the Washington DC Beltway that opened in November 2012 built by Flour and Transurban.
• I-15, between California State Route 163 and California State Route 78 in San Diego County. SOV toll ($0.50-$8.00); HOV-2+ free.
• I-680, southbound between California State Route 84 and California State Route 237 in Alameda and Santa Clara counties. SOV toll ($0.30-$6.00); HOV-2+, motorcycles, buses and eligible hybrids ride free.
• California State Route 237 between I-880 in Milpitas and North First Street in San Jose. SOV toll ($0.30-$6.00);
• I-85 in the Atlanta Area. Opened October 1, 2011. These lanes run between Old Peachtree Road and Chamblee-Tucker Road, including direct access to/from State Route 316, in Gwinnett and DeKalb counties. A Peach Pass is required for all vehicles including those exempt from tolling. The occupancy requirement for toll-free use is 3 or more people.
• I-95 Express near Miami, Florida. It currently runs from just north of I-395/SR-836 to the Golden Glades area just north of NW 151st Street in Miami-Dade County.
• I-95 Express Lane runs from Stafford, Virginia to the border of Alexandria, Virginia.
• I-95 Express Toll Lanes runs from the I-95 & I-895 junction to White Marsh, Maryland north of Baltimore.

Maximizing the public good

Traditionally, governments used traffic engineers to design highways for optimum traffic flow. For example, if usage increased, additional lanes would be added to a highway to accommodate increased traffic demand data. However, in some cases, where the HOT lanes are constructed by a private contractor and tolls are set based upon congestion pricing, the government gives up the right to expand the road or to build parallel roads. Some contracts call for the government to compensate the contractor for lost revenues if additional free lanes are built. For example, I-95 just south of Washington, DC was expanded from 3 lanes in each direction to 4 lanes until just past Occoquan. In 2017, terrible traffic backups occur where the road goes back to three lanes, and local governments and officials pressed to have the fourth lane extended south one additional interchange. The Virginia Department of Transportation declined to study the expansion out of fear that the HOT contractor has the first right to expand the road at that point and would also be entitled to compensation for lost revenues if the state built a non-tolled lane.