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Congestion Pricing Case Studies 127
6. San Diego Association of Governments
I-15 Express Lanes
The San Diego Association of Governments (SANDAG) is the metropolitan planning orga-
nization (MPO) for the San Diego County region, which comprises 18 city and county govern-
ments. SANDAG serves as the regional decision-making body responsible for transportation
planning and development. As part of these duties, SANDAG administers the local half-cent sales
tax--TransNet--providing funding for transportation projects. The sales tax was first approved
by voters in 1988 and was extended in 2004 for another 40 years. During the program's 60-year
span, it will generate over $17 billion, which will be distributed among highway, transit, and local
road projects in approximately equal thirds. In 2009, SANDAG collected over $1.1 billion in rev-
enue, approximately 25 percent of which was generated by the TransNet sales tax.
There are two operating toll facilities in the San Diego region: the I-15 Express Lanes, the first
dynamically priced HOT lanes, and the South Bay Expressway, a 9-mile privately financed toll
road with fixed pricing. SANDAG has been a leading innovator in the use of congestion pricing
and is dedicating a significant portion of the TransNet highway proceeds to developing a 75- to
80-mile network of managed lanes across four highway corridors identified in MOBILITY 2030,
its $42 billion regional transportation plan for San Diego County. San Diego is the first metro-
politan area in the United States to establish a long-range transportation plan featuring a regional
network of managed lanes as one of its primary strategies to meet future mobility needs.
SANDAG's primary goal in using pricing is to move people and goods more efficiently, rather
than raise additional revenue. SANDAG staff characterize HOT lanes as a small piece in the
regional plan of congestion relief. Their goal in implementing HOT lanes is to manage the num-
ber of vehicle in the lanes and thereby ease congestion in the parallel general-purpose lanes. Addi-
tional goals germane to congestion pricing and performance monitoring identified in MOBIL-
ITY 2030 include the following:
· Minimizing drive-alone travel by making it safer, more convenient, and efficient to carpool,
vanpool, ride transit, walk, and bike
· Responding to traffic congestion through greater emphasis on the Congestion Management
Program
· Applying new technologies and management strategies to make travel more reliable, con-
venient, and safe, and to reduce recurrent and non-recurrent congestion
· Measuring the performance and efficiency of the regional transportation system on a regu-
lar basis.
As reflected in these goals, SANDAG has an appreciation for the importance of performance
measurement. SANDAG's culture of performance management is also evident in the Conges-
tion Management Plans it has developed for all major highway corridors in the region. These
plans establish the parameters for expected corridor performance using travel demand model
and traffic simulation results and then use actual performance data collected by Caltrans' Per-
formance Monitoring System (PeMS) to verify whether the expected results are being achieved.
Through this process, SANDAG is constantly assessing whether or not it is meeting its conges-
tion management goals.
6.1. Overview of SANDAG's Congestion Pricing Program
Initially, the I-15 Express Lanes was an 8-mile, reversible, managed-lane facility built as an
HOV lane. It was then converted to HOT operation in 1996 because of significant underutiliza-
tion as an HOV lane. Capitalizing on the success of the initial conversion and its vision of
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128 Evaluation and Performance Measurement of Congestion Pricing Projects
developing a regional network of managed lanes, SANDAG is expanding the I-15 Express
Lanes to create a four-lane, 20-mile, barrier-separated HOT-lane facility with multiple access
and egress points. The expanded express lanes will feature a movable barrier allowing for
three travel lanes in the predominant direction of travel during peak periods, as well as direct
access to three transit centers with large park-and-ride lots. The expansion is being imple-
mented in three phases. The first, which opened to service in spring 2009, is an 8-mile segment
immediately north of the original I-15 Express Lanes between SR 56/Ted Williams Parkway
and Centre City Parkway in Escondido. The second phase, to extend the lanes north by 6 miles
from Centre City Parkway to SR 78, is slated for completion in 2011. The final phase of the proj-
ect will involve the retrofit of the original 8-mile segment between SR 56/Ted Williams Parkway
and Kearny Mesa. The entire construction of the facility is expected to be completed by 2012
and will operate 24 hours a day, 7 days a week.
The I-15 Express Lanes are available at no cost to HOV2 motorists, as well as transit vehicles,
motorcyclists, and approved low-emission vehicles, none of which are required to have ETC
transponders to use the lanes. SOV motorists must pay to use the Express Lanes, which feature
dynamic pricing with toll rates adjusted in 3-minute intervals. Tolls have been distance-based
since March 2009, with per-mile fees levied based on entry point. Toll levels are communicated
to motorists on variable message signs located upstream of entrances to the I-15 Express Lanes,
providing SOV drivers with the information and time they need to decide whether to use the
facility. While toll rates vary in real time, the minimum and maximum toll rates are capped at
$0.50 and $8.00 per trip, respectively, with a provision for HOV-only operation if less than LOS
C conditions on the lanes result even with the maximum allowable toll rate in place.
6.2. What Is Monitored?
The full spectrum of SANDAG's performance monitoring activities is provided in the accom-
panying Facility Performance Monitoring Summary Matrix for the I-15 Express Lanes. The
matrix is a comprehensive record of all current, known metrics used to monitor performance on
the facility, organized by evaluation category. It also includes earlier monitoring and evaluation
work performed by San Diego State University from late 1996 through 1999. Provided in the
matrix for each metric used are frequency of collection, purpose, a simple indication of impor-
tance, and particular characterizations of the metric that relate back to agency/facility goals or
applications. An expanded version of the matrix providing sources of information and other
notes is included in the Final Report for NCHRP 08-75 which is available on line. The matrix is
intended to be a visual overview of SANDAG's complete monitoring effort, easily comparable
to other HOT-lane facilities with similar matrix summaries. A more qualitative discussion of
how these metrics are applied in practice and which ones are the most significant is provided
below. Not all metrics noted in the matrix are discussed here.
SANDAG monitors several different performance parameters on the I-15 Express Lanes.
Using data reported automatically by its system operator, TransCore, SANDAG tracks the num-
ber of vehicles entering and exiting the I-15 Express Lanes, together with travel speeds, level of
service, vehicle density, and the distribution of paid and non-paid trips. SANDAG also monitors
revenue data reported by TransCore. All this data can be reported at different time intervals and
directions of travel.
The parameters described above are used to manage the I-15 Express Lanes and maintain
operations at LOS C or better at all times. SANDAG staff stated that by doing so they also deliver
consistent travel times on the I-15 Express Lanes. SANDAG stated the term "reliable" tends to
be qualitative, because customers' expectation when driving the road goes beyond travel time.
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Congestion Pricing Case Studies 129
Focus groups have shown that I-15 FasTrak customers feel safer and experience a more relaxing,
consistent trip using the facility versus the general-purpose lanes.
Given that SANDAG is expanding what was an 8-mile, two-lane facility with single points of
access and egress to a far more complex facility, it is also expanding its capabilities to monitor con-
ditions, through a $9 million I-15 Integrated Corridor Management contract awarded in January
2010. The capabilities and requirements of the new performance monitoring systems were being
identified as the research for NCHRP 08-75 was being compiled. One additional capability being
implemented as part of this effort is the ability to classify vehicles by type.
6.3. Other Essential Data Gathering Activities
SANDAG strives for transparency through an extensive outreach program, including focus
groups, public meetings, forums, and pricing discussions. SANDAG's most recent comprehen-
sive customer survey on the I-15 Express Lanes dates from 2001 and involved both quantitative
and attitudinal studies. The survey found that customers were "very happy" with the I-15 facility.
Given that it has been operating since 1996, FasTrak customers in the San Diego region under-
stand the complexities of the pricing algorithm, so there are limited questions and inquiries about
it. The survey confirmed that equity was not a concern among I-15 customers and stakeholders
and that the issue had been addressed through SANDAG's public information activities.
Subsequent survey work after the opening of the first segment of the expansion has not been
done because of the extensive construction activities in the corridor. Nonetheless, positive user
satisfaction with the HOT lanes continues to be achieved as evidenced by the lack of complaints
received by SANDAG or critical press. At the state level, there is some concern that HOV facil-
ities are not used as efficiently as they might be, and SANDAG has fielded questions about the
I-15 Express Lanes as a leader after which to model other facilities. SANDAG has also received
inquiries regarding the effect of HOT lanes on greenhouse gas reduction and supporting regional
transit with regard to the potential expansion of HOT lanes in the Bay Area.
As needs arise, SANDAG also assembles focus groups and small targeted surveys to learn more
about public opinion on specific performance issues, such as opinions on enforcement technology
and violation rates and different account plan options.
6.4. Why Performance Evaluation Takes Place and How Performance
Monitoring Data Is Used
As this research was being completed, the I-15 Express Lanes was at an important, yet pro-
tracted crossroads. The facility has been operating since 1996 and has demonstrated its perfor-
mance and utility to the region and local residents are used to it. This overall satisfaction with
the I-15 Express Lanes was arguably a contributing factor to the 2004 vote to extend the TransNet
sales tax to support the implementation of an aggressive package of transportation improve-
ments which were identified and widely publicized before the voting took place, including over
70 miles of new HOT lanes.
SANDAG is in the middle of a 5-year construction program to expand the I-15 Express Lanes.
Its current focus is on defining the monitoring metrics it will need to have in place in order to
manage the expanded facility when it is completed in 2012. In the meantime, the two-lane,
reversible lanes continue to operate as they have for the past 14 years, and a new, much more
complex segment has opened. At the same time, extensive construction activities in the I-15 cor-
ridor continue, affecting the operation of the general-purpose and managed lanes alike. More
performance data is available than ever before and is being used by SANDAG to operate a grow-
ing facility under dynamic circumstances.
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130 Evaluation and Performance Measurement of Congestion Pricing Projects Congestion Pricing Case Studies 131
Table 6-1. San Diego Association of Governments I-15 Express Lanes summary matrix.
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132 Evaluation and Performance Measurement of Congestion Pricing Projects
Current performance monitoring activities are used to ensure that policy and business rules
are maximizing the facility's efficiency, i.e., to manage traffic service on the HOT lanes at LOS C
or better and document that project revenues are adequate to cover the cost of operating the
facility. Using data obtained from ETC equipment and other detection devices installed at
tolling points on the lanes, toll rates are set in real time and reflect current traffic conditions detected
in 3-minute intervals. Traffic densities are calculated on a zonal basis to determine if congestion is
increasing. If so, an algorithm determines if other zones are experiencing congestion and sets the
price accordingly to manage the flow of traffic entering the facility using per-mile toll rate adjust-
ments. As congestion decreases, the algorithm lowers to attract additional traffic.
The maximum and minimum toll parameters that the algorithm uses to maintain LOS C on
the express lanes are mandated by policies established by SANDAG's Board. Meeting the traffic
service standard on the original 8-mile facility was straightforward. However, now that SANDAG
is operating a 16-mile facility, there are some notable limitations with the toll policies. Even so,
SANDAG has found that changing the established rates is not easy. For example, SANDAG's
recent attempt to increase the minimum toll from $0.50 to $1.00 was met with resistance from
the public as well as local radio personalities who argued that since the lanes are not a money-
making venture it was inappropriate to increase tolls. This dynamic is likely to continue as addi-
tional segments of the expanded facility are completed. However, SANDAG will have the benefit
of the performance data from its expanded monitoring program to make the case for adjustments
to the toll limits.
As mentioned earlier, SANDAG also uses focus groups and targeted surveys to study public
perception of specific issues and then uses the information gained to inform decisions. In addi-
tion, SANDAG will likely complete extensive public opinion surveys following the completion
of the expanded I-15 Express Lanes. The region's positive opinion of the project could help to
validate the continued expansion of HOT lanes and congestion pricing in San Diego County.
6.5. What Additional Performance Metrics or Data Would Be Helpful
to SANDAG or Other Agencies Considering Congestion Pricing?
Enforcement is difficult given that HOV and transit vehicles are not required to be equipped
with transponders. Although SANDAG has an anecdotal understanding of the effect of I-15
Express Lanes, in retrospect, staff wishes they had a quantifiable, measurable approach to doc-
ument the effect of pricing on such basic issues as traffic levels in the general-purpose lanes and
formation of carpools. SANDAG staff observed that the data they have collected on the exist-
ing I-15 Express Lanes only enables them to determine the effects of congestion pricing on SOV
utilization of the managed lanes.
SANDAG's experience with the expansion of the I-15 from its straightforward original con-
figuration to a complex 20-mile facility will be invaluable to other locations considering evolv-
ing existing HOT-lane facilities into more complex managed-lane systems. SANDAG staff report
that it has been challenging to manage the multiple new exit and entrance points, each of which
have different toll implications. They do not know if customers truly understand the price per
mile that they pay to use the lanes. Given the space constraints and safety implications, signage
conveying toll rates is particularly challenging for a complex facility such as the expanded I-15
Express Lanes. One possible approach for addressing this issue may be to use a matrix approach
to display toll rates by exit. The physical creation of many new entrances and exits to the man-
aged lanes as a result of the ongoing expansion affects monitoring metrics and procedures.
SANDAG is enhancing its monitoring capabilities in order to manage and operate the expanded
I-15 Express Lanes to full potential when construction is completed.
