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Ridematching facilitates ridesharing (carpooling or vanpooling)
by helping travelers find others with similar origins, destinations
and travel times who are also interested in carpooling for regular
or non-recurrent trips. Users access this information from the Internet,
intranets and office computers, home computers, interactive telephones
and pagers or simple paper match-lists.
Ridematching can be planned and executed on a daily or weekly basis
for regular commute trips that are fairly consistent and do not
change. Alternatively, ridematching can be dynamic such that an
independent organization matches passengers with drivers for individual
ad-hoc trips (as opposed to regularly scheduled trips), using telephone
and computer technologies. Thus dynamic ridesharing differs from
regular carpooling and vanpooling in that ridesharing is arranged
for individual trips rather than for trips made on a regular basis
and requests for ridesharing can be made close to the time when
the travel is desired. (Casey et al., 1996)
"Dynamic rideshare matching differs from traditional rideshare
matching in two important ways. The first major difference is the
treatment of the traveler's schedule. Traditional systems assume
the traveler has a fixed schedule and a fixed set of origins and
destinations (Michalak et al., 1994). A dynamic system must consider
each trip individually and be able to accommodate trips to arbitrary
points at arbitrary times by matching users' individual trips. The
second major difference is that dynamic ridematch systems must provide
the match information to the user quickly to accommodate near-term
(e.g. same day) travel as well as long-term (e.g. future days or
weeks) trips. Traditional systems frequently provide a matchlist
through paper mail, a process that may take more than a day (Puget
Sound Council of Governments, 1988; Walbridge, 1995). For these
two reasons, the requirements for dynamic rideshare matching are
more demanding than those for traditional rideshare applications."
(Dailey et al., 1999).
Ride matching services are provided by organizations such as CTS,
Inc. in Los Angeles, and RIDES, in the San Francisco Bay Area. These
organizations keep a database of subscribers, and generate several
hundred ride-match lists every week. Their focus is primarily long-term
users, that is, commuters interested in finding a carpool partner,
more than just a ride every once in a while. Conversely, the emphasis
of ITS ride matching systems is on dynamic ridesharing, although
they also offer more long term services. This is achieved by automatically
generating ride match lists upon request by interested parties.
Potential partners are matched on the basis of information pre-recorded
in the database, usually consisting of usual commute times, and
residence and workplace locations.
Three ride matching system field trials are reviewed here. One
was conducted as part of the Los Angeles SmartTraveler Field Operational
Test. The other was the Bellevue Smart Traveler, whose focus was
primarily ridesharing, although it also provided traffic and transit
information. The Seattle Smart Traveler provided dynamic ridesharing
services via the web and electronic mail at the University of Washington
in Seattle.
Los Angeles SmartTraveler
This test was a public/private partnership between the California
Department of Transportation, the Los Angeles County Metropolitan
Transportation Authority, the State of California Health and Welfare
Data Center, Commuter Transportation Services, Inc., Pacific Bell
and Pacific Bell Information Services, IBM Corporation, and North
Communications. Funding for the field test was provided by the State
of California, through the California Advanced Public Transit System
Program, and by the Federal Highway Administration, through earthquake
relief funds. In addition to ridesharing services, the field test
included pre-trip
information services.
The ridesharing service allows users to obtain lists of potential
ride matches, via touch-tone telephone. Users must pre-register,
which entails giving some personal information, including their
usual commute times and preferred pick-up and drop-off locations.
Upon request, the system can call the people in the list and deliver
an user-recorded message. The ridesharing materials were distributed
to 68,000 people.
Bellevue Smart Traveler
The BST project was led by researchers from the University of Washington,
in partnership with TransManage and with participation from PacTel.
The demonstration phase of the project took place between November
1993 and April 1994. The project was funded by the Washington State
Department of Transportation and by the Federal Highway Administration.
The main purpose of the Bellevue Smart Traveler (BST) is to facilitate
ridesharing (carpooling), but it also provides traffic and transit
information. The ridesharing service operates by subscription: once
registered, a participant is entitled to offer rides, and to accept
rides offered by other subscribers. The system is available via
telephones and pagers.
The field test tracked the supply and demand for rides over a five
month period. Test participants were selected based on their residence
location (all participants worked in the same office complex). Three
ridesharing groups were formed, with membership varying from 8 people
in the smallest group to 27 people in the largest.
Seattle Smart Traveler
The Seattle Smart Traveler (SST) tested a dynamic ridematching system
using the Internet and electronic mail (e-mail) at the University
of Washington in Seattle. The project was part of the Seattle Wide-Area
Information for Travelers (SWIFT), a larger Intelligent Transportation
System Field Operational Test conducted by the Washington State
Department of Transportation, the University of Washington, King
County Metro, and five private sector partners, with funding from
the Federal Highway Administration.
The dynamic ridematching system was developed and operated at the
University of Washington from 1995 to 1997. The system was designed
by researchers in the Department of Electrical Engineering using
a World Wide Web or Internet interface. A number of technologies
and techniques were considered for the system. The combination of
a Web Page on the Internet and e-mail was selected based upon availability
to the target user groups. These systems are available on a 24-hour
basis to students, faculty, and staff at the University. In addition,
individuals in these groups tend to be computer literate and use
e-mail and the Internet on a regular basis. The SST was designed
to meet the needs of individuals interested in forming ongoing carpooling
arrangements, as well as those interested in offering or obtaining
a ride for a single trip. Two of the unique elements in the system
design were accommodating the desired travel times and identifying
origins and destinations.
To provide flexibility in the matching of trips, a time range or
window was used for both the requested departure and arrival times.
A search structure was developed using a series of pull-down menus
allowing users to easily identify their desired origins and destinations
from a search tree containing four levels of detail. Although the
design of the SST was relatively complex, the system was easy for
participants to access and use. A potential participant first accessed
the Web site by entering either their student or staff identification
number or user password. The individual then completed an SST application
form, which included their telephone number and e-mail address,
but not their home address. The participant could request a trip
at the time they registered and on an ongoing basis. Three types
of potential matches could be requested. These were regular commute
trips, additional regular trips, and occasional trips. A user entered
the origin, destination, day of week, departure time, and arrival
time for each trip type they would like to check for a rideshare
match. (Assessment of the Seattle Smart Traveler, FTA, 1999)
Approximately one half of all participants in
the Bellevue test had carpooled before, and about 25% had done so
on a regular basis (four or more times a week). At the time of the
demonstration project, about half of all participants commuted to
downtown Bellevue in single-occupant vehicles, 35% carpooled or vanpooled,
and the remainder 15% traveled by bus. Several reasons were cited
for joining a ride group; some of the most popular were: to find an
occasional carpool partner (61%), out of curiosity (57%), to save
time and/or money by carpooling (36%), out of interest in traffic
information (21%), and to find a regular carpool partner (11%).
Moreover, the city of Bellevue was considered a good site to try
carpooling services, because it exhibits radial commuting patterns,
as well as peak hour congestion: employment is concentrated in the
downtown area, and workers' residences are located in the suburbs.
It was found that approximately 2/3 of auto commuters have little
knowledge of the availability of transit services to downtown Bellevue,
or of its cost. But some commuters, especially low-income commuters,
expressed interest in switching to transit or to carpool if more
information was available about these alternatives.
Users of the Los Angeles SmartTraveler ridesharing service tended
to have longer trips to work than the average Los Angeles County
commuter, and were less likely to drive alone. Of all users, 18%
used alternative modes to get to work about once or twice a week.
Users stated that circumstances for which their regular commuting
mode was not available are rare, suggesting that demand for occasional
carpooling is likely to be low. Other factors that may lower the
demand for carpooling are that half of those surveyed said they
sometimes work a schedule different from their regular one, and
that sometimes their work takes them to places other than their
office. About half of all users felt they have access to good transit
service. Most felt they needed transit and carpool information,
yet at the same time most refused to ride with strangers.
Approximately 400 individuals used the SST dynamic ridematching
system during the demonstration. The ongoing monitoring by University
of Washington staff and the survey results provided the following
information on SST participants:
-
Faculty and staff comprised approximately 68 percent of the
users, while students represented 32 percent. Student use increased
in the fall and winter of 1996, however.
-
The vast majority of the participating faculty and staff had
regular work hours. The student’s schedules varied more by day
of the week, but approximately 60 percent indicated fairly regular
commute schedules.
-
Most participants were regular users of e-mail and the Internet
and most reported being able to access both systems at home
and at work.
-
Thirty-eight percent of the respondents normally commute by
bus, while 37 percent carpool, 25 percent drive alone, and 5
percent bicycle.
-
Thirty-five individuals said they would use SST for a match
when their normal commute mode was not available, although most
noted that they normally ask a friend for a ride.
Over the five-month period of the demonstration project, 509 rides
were offered and 148 rides were looked for using a telephone. Of
these, on 33 occasions the caller requested more specific information
about a ride offer. The system did not keep track of pager-based
searchers. Users need not log when a ride match was found, as this
function was optional. As a result, the system reported only six
logged matches. It was later found that several people used their
pager, instead of the telephone, to seek ridesharing information
and traffic or transit information.
Self-reported usage is shown in Table 1. Users were more likely
to offer than to take rides. There was also a large proportion of
participants who actually did not participate in ridesharing activities:
almost one half of all registered users never looked for a ride,
while about 25% never offered a ride.
Table 1
Self-reported Usage of the Bellevue Smart Traveler
| Frequency |
Looked for a Ride |
Offered a Ride |
Never |
48% |
25% |
| Less than once a week |
26% |
21% |
| Once to three times a week |
22% |
50% |
Source: Haselkorn et al., 1995.
Use of the ridesharing service appears to be seasonal: it increases
on bad weather months. On average, the system logs 205 calls per
week, far below the demand for ridesharing serviced by Commuter
Transportation Services (CTS). In fact, although ARMS covers about
10% to 30% of the region covered by CTS, it receives roughly only
3% of the ride-match phone calls, and it generates only one match
list for every 500 lists generated by CTS every week.
An intercept survey of callers (sample size=24) indicated that
use is fairly irregular: 60% had used the system less than twice,
and the vast majority were looking for a regular carpool partner,
as opposed to a one-time ride. Only three out of the 20 people who
attempted to contact those in their match list were able to arrange
a ride.
An experiment was conducted to establish how successful the system
was in finding occasional carpool partners. Fifteen "fictitious"
people were registered in the ridesharing database, and each day
for eight weeks, a researcher called to try to arrange a ride for
one or two of them. The results of this experiment indicated that
chances of getting a ride were about 20% when the user personally
called each person in his/her match list, including some conditional
offers. Thirty-six percent of those contacted did not return the
call, 28% could not offer a ride that day, and 16% stated they would
never offer a ride. These results confirmed users' suspicions that
the database was not updated regularly enough, and that it was not
large enough to support ridesharing. The automated message feature
performed poorly: it could not be accessed half of the time, and
it resulted in a no-response rate of 93%.
Use of the SST dynamic ridematching system was tracked by University
of Washington researchers over the 15-month demonstration. In addition,
two surveys were conducted during the last month of the test. First,
an e-mail survey was used to obtain information from participants
who had requested a rideshare match or who had been on a match list.
Second, a survey on the SST Web Page allowed all participants to
provide general comments on the system and feedback about the test.
Figure 1 highlights the number of registered participants in the
SST. Approximately 400 individuals registered for the SST through
November 1996, with the actual number of active participants varying
over the course of the demonstration.
Figure 1: SST Use

Source: Assessment of the Seattle Smart Traveler,
FTA, 1999
As illustrated in Figure 1, participation grew during the spring,
summer, and fall of 1996. The largest number of active participants
occurred in the spring and fall of 1996 when some 200 individuals
were in the SST database. Figure 1 shows the periods at the end
and the start of each quarter when the SST database was updated
to eliminate individuals no longer wishing to participate. Although
purging these individuals from the database reduces the total number
of participants, and the potential pool of rideshare matches, it
enhances the likelihood that possible matches will actually result
in a successful carpool.
Figure 1 also includes the number of University of Washington students,
faculty, and staff registered in Metro’s ridesharing program. There
was only a 20 percent overlap of individuals registering for both
programs, indicating that they served different clientele. University
researchers also tracked the time of day participants accessed the
SST. Approximately 20 percent of the system use occurred outside
the normal business hours of 8:00 a.m. to 5:00 p.m.. As noted previously,
one of the reasons for selecting the Internet for the test was the
ability to access the system on a 24- hour basis.
A total of 2,065 trips were registered in the database over the
course of the demonstration. Figure 2 presents the cumulative number
of attempted matches, the cumulative number of successful matches,
and the cumulative number of e-mail messages sent to form a carpool.
Approximately 700 matches were requested. Of these, some 150 matches
(21 percent) were established. The individuals requesting the match
were provided with the names of potential riders. At least 41(about
six percent) individuals actually established a carpool for the
requested trip.
Figure 2: SST Matches

Source: Assessment of the Seattle Smart Traveler,
FTA, 1999
The Bellevue field test included personal interviews, to learn about
participants' opinion of the service. Several reasons were voiced
about the inconvenience of ridesharing: uneasiness about getting
into a stranger's car, busy and/or erratic schedules, complex lifestyles.
Several people complained about offering rides and not receiving
responses; as a result they became very discouraged. This was partially
attributed to the fact that some of the ride groups were too small
to sustain dynamic ridesharing activities.
Additional reasons mentioned for not forming carpools include:
- Never receiving calls from interested riders
- Never finding a ride at a convenient time
- Often rides were offered one way only
- Having an unpredictable work schedule
Participants thought that addressing the following issues would
encourage carpool formation:
- Getting participants to know each other
- Knowing other participants' home location with respect to own
- Agreeing on predetermined pick up points
- Knowing participants' scheduled commute times
- Making the system more user-friendly
- Having HOV lanes on the route to work
- Making sure participants cleared a police check
As noted, approximately 400 individuals used the SST dynamic ridematching
system during the demonstration. The ongoing monitoring by University
of Washington staff and the survey results provide the following
information on SST participants and their use of the system:
-
Of the 141 participants responding to the e-mail survey in
May and June of 1997, 31, or 22 percent, indicated that they
did share a ride with someone as a result of using the SST.
-
Forty-five individuals responded to the survey on the SST Web
Page. This survey focused on the ease of use of the Web Page
and SST system, normal commute modes, and general reactions
to the test. The overall comments were positive related to use
of the SST system. A few respondents suggested that the length
of the forms and the process may inhibit some potential users.
-
Thirty-five individuals said they would use SST for a match
when their normal commute mode was not available, although most
noted that they normally ask a friend for a ride.
-
The SST may have been viewed by some potential users as too
temporary or too experimental. As noted in Chapter Three, some
of the news articles and information in the U-PASS brochure
noted that the SST was a temporary program and that it was operated
by researchers in the ITS program. These types of comments may
have led some students, faculty, and staff to think of the SST
as an experiment or research project rather than a ongoing service,
and may have limited their participation.
-
One limitation to ridesharing continues to be concerns about
sharing rides with strangers. Although some of the features
of the SST were designed to help address this concern, the system
was not able to overcome this issue.
The first dynamic ridematching projects, the Bellevue Smart Traveler
and Los Angeles Smart Traveler, generated very low levels of matches.
Participants were amenable to the dynamic ridesharing idea, liked
the technology and presentation of information, but were unwilling
or unable to form rides for a variety of reasons. Ridematching systems
were initially limited by several factors including:
- The participant base was often too small to ensure sufficient
matches.
- Projects were implemented a little before the real boom in
Internet use.
- Technologies available at the time for developing dynamic ridematching
systems were somewhat cumbersome.
- Initial projects may have been viewed by some potential users
as too temporary or too experimental.
- Insufficient incentives to help promote ridesharing such as
HOV lanes, parking incentives, and other techniques to encourage
carpooling.
- Safety concerns: commuters were often reluctant to travel with
strangers.
More recent dynamic ridematching projects, such as the Seattle
Smart Traveler (SST), generated match and carpool levels that approximated
the numbers of traditional rideshare programs. In fact, the SST
was operated in parallel to a traditional, regional rideshare system
for one year and the two systems were marketed to the user community
on a side-by-side basis. The SST and the traditional system acquired
approximately the same number of users, although there was little
overlap in the user populations using the parallel systems. The
project thus demonstrated that there was a user population (not
reached by traditional methods) that could be reached using the
Internet for dynamic ridesharing services.
As use of the Internet increases rapidly, new communication devices
proliferate and congestion worsens, use of ridematching services
could grow beyond the numbers achieved by traditional rideshare
programs.
Ridematching has travel impacts to the extent that it encourages
ridesharing. Rideshare programs which include incentives (parking
reductions and HOV lanes) often reduce commute trips by at least
10% (Winters and Rudge, 1995). If implemented without such incentives
travel impacts are often smaller. The most effective programs tend
to have paid parking, subsidies for alternative modes, and other
incentives to encourage reduced automobile commuting.
Because rideshare passengers tend to have relatively long commutes,
mileage reductions can be relatively large. For example, if ridesharing
reduces 5% of commute trips it may reduce 7% of vehicle miles because
the trips that are reduced are longer than average commutes. Rideshare
programs can typically reduce up to 8.3% of commute VMT, up to 3.6%
of total regional VMT, and up to 1.8% of regional vehicle trips
(Apogee, 1994; TDM Resource Center, 1996).
- Congestion Reduction : Reduces peak-period automobile travel.
- Road & Parking Savings : Reduces peak-period automobile travel.
- Consumer Savings
- Transportation Choices : Increases travel choice.
- Road Safety : Reduces vehicle mileage, but increases vehicle
occupancy, so crashes that do occur may have more casualties.
- Environmental Protection : Reduces automobile travel.
- Community Livability : Reduces automobile trips.
Cost data are available for the Los Angeles SmartTraveler field
test only. Direct installation costs include development and marketing
costs, while direct operational costs are primarily those of providing
modem access and a phone line for data transfer. To estimate cost
per use, it was assumed that each port costs $220 per month, and
that it can service 150 calls per week (50% utilization rate); the
phone line was estimated to cost $1.0 per use. Initial development
costs were estimated at about $150,000.
Assuming a level of use similar to that experienced during the
test, the ridesharing service would cost $110 per use for a one-year
lifetime, or $27 per use for a five-year lifetime. This assumes
no additional expenses for marketing and promotion. If installation
costs are assumed to be sunk costs, then the cost per use would
be approximately $3.
Costs to participants may include additional travel and time needed
to meet rideshare partners, schedule constraints needed to match
commuting times, loss of privacy, and restrictions on stops for
errands.

Source: Giuliano et al., 1995
Rideshare matching services are usually open to anyone in a particular
geographic area. Most ridesharing services are self-supporting.
Most rideshare matching services are subsidized but the costs are
usually modest, much smaller than the social cost of accommodating
automobile travel. For example, if a ridematching service is effective
at reducing just a few percent of automobile trips, its expenses
can be paid through reduced road and parking facility costs. Rideshare
programs generally increase vertical equity by improving travel
options for non-drivers and making commuting more affordable (Source
Victoria Transport Policy Institute, TDM Encyclopedia).
The chief barriers are:
- Lack of a large enough pool of travelers to form matches.
- Lack of appropriate incentives to help promote ridesharing
(HOV lanes, parking incentives etc.)
- Reluctance of potential carpoolers to travel with strangers:
a ridematching system that had a security screening process might
help address this issue.
- Lack of marketing: potential users need to be informed of this
option.
The effectiveness of ridematching projects can be enhanced by addressing
the aforementioned barriers to implementation. Additionally, implementers
should keep in mind that:
-
Ridematching services should cover a large geographic area
(such as an entire region) in order to create the largest possible
pool of users.
-
Transportation agencies, businesses and employees should all
be involved in planning rideshare programs.
(including traditional rideshare programs)
These are excerpted from the VTPI
TDM encyclopedia.
Commute Trip Reduction Rideshare Programs
Comsis (1993) and Pratt (1999) describe several successful rideshare
programs, including the Commuter Transportation Services, which
provides ridematching services in Southern California, an employment
center ridematching service supported by businesses, a residential
ridematching service provided to residents of a suburban community
funded by a developer, and various vanpool programs.
Dynamic Ridesharing in Seattle (http://sst.its.washington.edu/sst)
Metro Vanpooling Program (http://transit.metrokc.gov)
Seattle’s Metro transportation agency provides ridematching services
throughout the region and operates dozens of self-financing vanpools.
Below are their instructions for organizing one:
You need four other people, in addition to yourself -- or as many
as 14 -- to organize a vanpool. The more people, the lower your
fare. Once your pool is together, you need to decide on a route,
pick-up points and schedule. Choose a primary driver and at least
one back-up. Primary drivers, who meet Metro requirements, ride
free and may receive 40 free personal miles each month.
The Minerva System uses cellular phones, palmtop computers, and
wireless data communications to provide low-cost, door-to-door
transportation
in low-density areas and low travel corridors. The service can
be integrated with conventional transit, paratransit and ridesharing
services, plus consumer services such as home shopping, telebanking
and e-mail, to help reduce the need for some trips altogether.
The
Oregon State legislature has committed $1.5 million to this project,
with additional commitments of $3 million in matching funds from
local pilot sites, and $1 million in in-kind support from private
management consulting outfits.
San Francisco, CA
Approximately 8,000 to 10,000 people, or nine percent of total
carpoolers, participate in casual carpooling in the San Francisco
area. During the morning commute periods, pick-up points are in
Oakland near Bay Area Rapid Transit (BART) stations and in Alameda-Contra
County near Costa Transit bus stops. These sites serve as loading
zones, provide users with a back-up choice if a ride is unavailable,
and guarantee users a ride home in the evening. Drop-off points
usually are near the Transbay bus terminal in downtown San Francisco,
although other destinations are also common. These sites are centrally
located and provide passengers with other means to continue their
trip if needed. Carpoolers gain the benefit of a 10 to 20 minute
timesavings while avoiding a $3.00 toll by using the HOV toll
bypass
lane; passengers save money. Limited
evening casual carpooling is underway, thanks to a 20-mile HOV
lane constructed on I-80, though there is a problem with the greater
dispersal of destinations at night.
Washington, DC
Casual carpooling in the Washington, DC area is well established
with approximately 3000 people, or 11% of carpoolers, doing it.
Northern Virginia commuters, who want a ride to the Pentagon or
Washington DC, stand at specific suburban locations, usually near
parking lots or bus stops. Drivers wanting to legally use the HOV
lane system pick them up. Destinations are usually announced, except
in certain places where drivers stand in queues according to which
bridge they want to cross. A similar arrangement is used for the
return trip from DC, but rides are harder to find causing some passengers
to take transit home in the evenings. Drivers save up to an hour
or more on their commute time and commute times may be more reliable;
passengers find that casual carpooling is normally faster and more
flexible than bus or subway service because of the ease and speed
in which a ride is obtained and cheaper because they are not paying
fares.
Beroldo, Steve Ridematching System Effectiveness: A Coast-To-Coast
Perspective Transportation Research Record 1321, 1991, pp. 7-12.
Beroldo, Steve Casual Carpooling in the San Francisco Bay Area
Transportation Quarterly, January, 1990, pp. 133-150
www.carpool.ca
Commuter Connections promotes the development of rideshare programs
and provides technical support
Commuter
Choice Program, Transportation Air Quality Center, USEPA.
D. J. Dailey, D. Loseff, D. Myers, and M.P. Haselkorn, The
Seattle Smart Traveler, Transportation Research Board Annual Meeting,
University of Washington, 1997.
Guiliano G, R.W. Hall, and J.M Golob. Los
Angeles Smart Traveler Field Operational Test Evaluation. PATH
Research Report PRR-95-41. University of California at Berkeley,
Institute of Transportation Studies, 1995.
Haselkorn M., J. Spryidakis, C. Blumenthal, S. Michalak, B. Goble,
and M. Garner. Bellevue
Smart Traveler: Design, Demonstration, and Assessment. Final
Technical Report. Sponsored by the Washington State Department of
Transportation, Report No. FTA- WA-0039-95-1. Seattle, Washington
State: University of Washington, Washington State Transportation
Center, 1995.
Sacramento Council of Governments provides information on ridesharing
in the Sacramento area, and a cost calculator.
Seattle
Smart Traveler was an dynamic ridematching test program that
operated in Seattle, Washington, from 1995 through 1997. Although
no longer functioning, the website describes the program.
U.S. DOT, Assessment
of the Seattle Smart Traveler Evaluation; Sept. 1999
Traks:
Excellent website with transportation management information for
the San Francisco Bay area and a commute calculator.
Victoria Transport Policy Institute, Ridesharing,
August, 2000. Excellent report from the VTPI Travel Demand Management
encyclopedia (an excellent resource on TDM).
Authors: Dimitri Loukakos and Rosella
Picado. Last update: 11/01/00
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