High occupancy/toll and express toll lanes
||The examples and perspective in this article deal primarily with the United States and do not represent a worldwide view of the subject. (February 2013)|
High occupancy/toll lanes (HOT lanes) is a road pricing scheme that gives motorists in single-occupant vehicles access to high-occupancy vehicle lanes (or "HOV lanes"). Sometimes, entire roads are designated for the use of HOVs. Tolls are collected either by manned toll booths, automatic number plate recognition, or electronic toll collection systems. Typically, these tolls increase as traffic density and congestion within the tolled lanes increases, a policy known as congestion pricing. The goal of this pricing scheme is to minimize traffic congestion within the lanes.
Express toll lanes (ETLs) is a similar concept. The main difference between HOT and ETLs is that, in HOT lanes, HOVs are granted free access, whereas in ETLs all vehicles pay according to the same schedule. In a third type, called hybrid lanes, HOVs pay a reduced toll.
Variable tolls 
HOT lanes and ETLs require single-occupant vehicles to pay a toll that varies based on demand, called congestion pricing. The tolls change throughout the day according to real-time traffic conditions, which is intended to manage the number of cars in the lanes to keep them less congested.
In the Los Angeles Metro ExpressLanes HOT system, special "switchable" transponders are used on which the driver of a vehicle indicates the number of occupants (including him or herself) by setting a switch on the transponder. Based on the setting of this switch, the electronic toll collection system automatically determines whether or not a toll should be charged, also taking into account variable HOV restrictions (such as HOV being considered three or more occupants during peak hours and two or more occupants at all other times). For enforcement, a beacon light near the receiver lights when a transponder is scanned. The light indicates to highway patrol officers the setting of the occupancy switch of a car's transponder, and the car can then be visually checked to see if there are more or less people in the car than indicated on the transponder.
The HOT lanes concept is an expansion of HOV lanes that allows single-occupant vehicles to also use the lanes, by paying a toll and thus generating a profit. Proponents claim that all motorists will benefit from HOT lanes, even those who choose not to use them. This argument only applies to projects that increase the total number of lanes. Proponents also claim that HOT lanes provide an incentive to use transit and ride sharing.
Because HOT lanes and ETLs are often constructed within the existing road space, they are criticized as being an environmental tax or perk for the rich ("Lexus lanes"). Those who criticize the concepts claim that the lanes provide congestion relief to the motorists of a higher socioeconomic class. With HOT and hybrid lanes, the attempt to address this criticism typically consists of special treatment for HOVs. Personal vehicles carrying more than a specified amount of passengers (typically two or three) are permitted to use the HOV lanes at a reduced toll (hybrid lanes) or for free (HOT lanes). Additionally, public transit vehicles are typically exempted from the toll. A counter-argument is that the rich often already have ways to ease their commute that are not available to the poor, such as buying a home closer to where they work.
No existing highways are 100% ETL, but there are several HOT and hybrid systems. The only fully ETL roadway in design/construction is in Maryland, along the John F. Kennedy Memorial Highway (Interstate 95) as it travels through Baltimore and Baltimore County. The project will add two express toll lanes in each direction, supplementing the existing four general purpose lanes in each direction.
|This article is outdated. (March 2012)|
Planning for the project took place as part of an I-95 master plan process conducted by the Maryland Transportation Authority. Construction on the I-95 project began in 2006 and is expected to conclude in 2014. The state of Maryland has indicated its interest in exploring the addition of ETLs to other state highways on a case-by-case basis. Other roadways currently being studied include I-270 and the Capital Beltway.
Funding and construction 
Implementation of these systems can be prohibitively expensive, due to the initial construction required—particularly with regard to providing access to and from the express toll lanes at interchanges. However, the long-term benefits—the decrease in delay to motorists and increased funding for the transportation agency—may outweigh the costs. To offset costs of construction, many transportation agencies lease public roads to a private institution. As a result, construction may be partially or fully funded by the private institution, which receives all of the income from tolling for a specified period of time.
See also 
- FAQ - VA I-495 HOT Lanes Retrieved October 6, 2009
- Brookings Institution economic study on HOT Lanes
- MD I-95 Express Toll Lanes Retrieved October 6, 2009
- Northern Virginia Transportation Alliance
- Golden Gate Bridge for variable toll
- "FAQs: FasTrak". Metro ExpressLanes. Los Angeles County Metropolitan Transportation Authority. Retrieved March 3, 2013.
- "FAQs: Driving Metro ExpressLanes". Metro ExpressLanes. Los Angeles County Metropolitan Transportation Authority. Retrieved March 3, 2013.
- Metro ExpressLanes: Rules of the Road (YouTube). Los Angeles County Metropolitan Transportation Authority. July 24, 2012. 2 minutes in.
- About I-495 HOT Lanes Retrieved August 31, 2009
- MTC Planning - HOV/HOT Lanes Retrieved October 6, 2009
- MD ETL Statewide Revision 200607 Retrieved October 8, 2009
- A Guide for HOT Lane Development (FHWA, 2003)
- Review of Road Pricing to Reduce Congestion - 2012, U.S. Government Accountability Office - includes evaluation of 21 HOT lane projects in the U.S.