Real-Time Ridesharing

Introduction

Real-time ride-sharing (also called dynamic or instant ride-sharing) is an automated system that matches drivers and riders on very short notice.¹ This differs from formal ride-sharing in that it does not require pre-planning or regular scheduling. Though most commuters prefer to pre-plan trips at least the night before,² real-time ride-sharing promotes carpooling regardless of the available planning time.

Real-time ride-sharing without technology, also known as slugging, is sometimes used to qualify for high-occupancy vehicle (HOV) lane use. Riders may stand at bus stops near HOV entrances to wait for a ride. If the rider is near a bus stop, he or she has another travel option (transit) as a safety net in case a single driver does not arrive.

Using technology for ride-sharing, however, can improve the safety, efficiency, and overall service for all roadways. Smartphone apps can be used to:

Locate likely drivers.
Provide information on drivers to help users decide if they would like to share a ride.
Offer an automatic payment system to pay the driver without exchanging cash.

Ride-share drivers can benefit from:

Lower travel time by qualifying as a carpool in a managed lane.
Potential monetary gain from sharing expenses with the rider.

Researchers have estimated savings in vehicle miles traveled from real-time ride-sharing programs ranging from 6 percent to 27 percent.³

Executive Summary

Target Market

The number of participants in a ride-sharing program must be high enough to offer users a good chance of finding a match.² Thus, identifying a good market for a range of trip types is important. Traditional carpooling is efficient for regular commuters, but real-time ride-sharing is also useful for other trips. The 2009 National Household Transportation Survey reports that 28 percent of U.S. vehicle miles traveled are commute trips. Based on this, real-time ride-sharing can expand carpooling beyond the daily commute.

Although real-time ride-sharing can work for any vehicle trip, the following groups may benefit most:

People in areas not well served by transit.⁴
People in city/town activity centers.²
HOV or high-occupancy toll (HOT) lane users seeking passengers or drivers.⁵
People comfortable with computer and cell phone messaging.²

How Will This Help?

Reduces congestion by decreasing cars on the road and increasing HOV lane use.
Lowers commuting costs for users by sharing costs or eliminating the need for a car.
Decreases auto emissions by removing cars from the road and allowing more efficient speeds.

National Household Transportation Survey data show the number of vehicles per household rose over 13 percent between 1977 and 2009. Meanwhile, the average number of people occupying vehicles decreased 24 percent over the same period. These statistics have changed over recent years due to economic and other factors, but the overall trend is not expected to change immediately. Real-time ride-sharing could improve the efficiency of roadway infrastructure by increasing the average number of riders in a vehicle.

Implementation Examples

Real-time ride-sharing is increasing in the United States, but widespread adoption has been much faster in Europe. Technology-assisted ride-sharing is relatively new in the United States.

Casual Carpooling
Though much of the current focus on real-time ride-sharing involves the use of technology, users in Houston, San Francisco, and Washington, D.C., often use casual carpools, or slugging, to meet HOV lane requirements. Slug lines form at meet-up points like park-and-ride lots or local businesses upstream of HOV lanes. In the evening, slug lines near employment places reverse the flow of carpoolers.

San Francisco’s casual carpooling community has 22 morning pick-up points, with approximately 150 daily carpools per location.⁶ One study estimated that casual carpooling in San Francisco saves between 449,000 and 924,000 gallons of gasoline per year, or 53 to 106 gallons per person annually.⁶ The same study also estimated savings related to carbon dioxide emissions, time, buses not purchased, and bus operating costs exceeding $30 million per year. This figure includes added efficiency to general-purpose lanes.

Carma Austin
The Central Texas Regional Mobility Authority and Carma studied the use of real-time ride-sharing technology to support charging different tolls based on occupancy.⁷ In the study, Carma’s ride-sharing app recommended drivers and riders for sharing trips. Researchers then evaluated the use of a discounted toll on two tollways for study participants:

A two-person carpool got half of the toll reimbursed.
A three-plus person carpool got the full toll amount back.

Toll reimbursements occurred monthly and were credited to a registered TxTag account. The pilot program concluded in December 2014. The program’s impact on vehicle occupancy and the impacts of toll discounts was evaluated.

Application Techniques and Principles

Employer and Residential Marketing
Real-time ride-sharing needs a large number of participants in order to support a variety of users and trips. Marketing new programs to large companies is sensible because employees will have similar travel patterns. Residential-focused social marketing can also be effective for encouraging carpooling.⁴

Encouraging Multiple Passengers
Maximizing the number of people in a vehicle increases efficiency and promotes trust between driver and passengers. Early research found three-plus carpools had fewer trust concerns.⁵ Having another carpooler makes a shared trip feel more like transit.

Issues

Agency Liability
Local public agencies have expressed concern about real-time ride-sharing programs due to fears of liability and profit reduction. Several companies have addressed this issue by assigning safety liability to the user.

Critical Mass
Having enough participants is key to the success of real-time ride-sharing in a given area. Having a large number of participants increases awareness of the program and likely involvement in it. A study in Canada found closeness to carpool lots and urban versus suburban location were not as important as residential access to other ride-sharing users.⁴

Technology Adoption
Smartphone-enabled ride-sharing may promote spur-of-the-moment use, but not everyone has access to the phone or data plan required. Eighty-five percent of cell phone owners ages 18 to 29 go online with their phones, but only 22 percent of seniors 65 and older do so.⁸

Still, opportunity for increased access exists in low-income communities. Members, who were previously unable to afford both a computer and Internet connection, are increasingly buying smartphones.

Taxi Regulation
The methods and rates related to ride-sharing fees are an important concern. Several cities have challenged companies such as Uber, Lyft, and Sidecar for operating like taxi companies without following the same permitting and safety requirements. These companies often reply that they are offering a “transportation network service” rather than a direct transportation solution like a taxi company.

The federal definition of real-time ride-sharing⁹ states that cost recovery cannot exceed the cost of the trip provided. This definition distinguishes between taxi-like services that make money from trips and ride-sharing, where costs are shared. Under this definition, there is no financial motivation for a driver to pick up a passenger beyond sharing the cost of a trip.

The difference between ride-sharing and taxi-like services can also be about reducing the total vehicle miles traveled through ride-sharing versus profiting by making extra trips, like a taxi service.

Who Is Responsible?

Private real-time ride-sharing providers and users deploy the service, most often without public agencies. However, several pilot programs have been sponsored by local public agencies. Marketing and incentives from transportation management associations may help.

Project Time Frame

Real-time ride-sharing is already available in most large cities in the United States, though it may not be well known. The time needed to measure large-scale impacts on the transportation system is unknown. Further research on adoption will be helpful to develop programs in new areas.

Cost

There is no direct cost for public agencies since the systems handle ride-sharing payments between drivers and riders. Individual costs to participate are typically a percentage or a set fee per trip.

Actual personal costs for one system are 20 cents per mile for riders; 3 cents goes to the company, and 17 cents goes to the driver. At least one company caps this reimbursement to not exceed Internal Revenue Service rates for the cost of the trip in order to meet the federal definition of ride-sharing⁹

Data Needs

Real-time ride-sharing apps currently work with smartphones, using global positioning system (GPS) locations. Only the driver and rider information agreed to by participants is delivered over cellular or wireless transmission. Research organizations must arrange for use of selected data, subject to institutional review board approval, to ensure appropriate data use. Pilot studies or incentive programs can be designed based on population and local needs.