Core performance measures, shown in
Figure 9, focus attention on relevant topics and objective
information. Use of this list of core
performance measures provided for an informed discussion of a variety of
transportation strategies, actions, and projects throughout the New Visions process. The core measures also help identify the
magnitude of the challenge facing the Capital Region in attempting to attain
the system goals stated above. A more
detailed discussion of New Visions
performance measures can be found in the New
Visions Workbook Technical Appendix and other reports shown on page 215.
Figure 9:
Core System Performance Measures
Transportation Service
Access: What
travel alternatives exist? (% of person trips within a defined non-auto
(walk, bike, transit) to auto time difference[1]; % of person trips with a travel time advantage
for non-drive-alone modes (including carpools); # or % of major freight
movements with modal alternatives[2])
Accessibility: How much time
does travel take? (travel time between representative
locations, including major intermodal facilities; peak vs. non-peak, by
quickest mode)
Congestion: What is the
level of exposure to traffic congestion?
(excess delay: recurring,
non-recurring by mode [auto, transit, freight, bike, pedestrian][3])
Flexibility: Can the
system respond to unexpected conditions?
(reserve capacity on system[4]; percent of person trips that could be
accommodated by modes other than auto in an emergency[5]; # of corridors with reasonable alternatives during
closure or disruption[6]; amount of risk associated with fixed capacity
investment[7])
Resource
Requirements
Safety: What
are the safety costs associated with transportation? (estimated
societal cost of transportation accidents)
Energy: How
much energy is consumed in providing, maintaining and using the transportation
system? (equivalent gallons of fuel/day for transportation capital,
maintenance, operation and use)
Economic Cost: How much does the
transportation system and its use cost, in addition to safety and energy costs? (Annualized
capital, maintenance, operating and [monetary] user costs for transportation
system; value of commercial time in travel)
External Effects
Air Quality: What is the
effect of the transportation system on air quality? (Daily
emission levels (HC and NOx); air quality attainment status)
Land Use: How does the
transportation system affect land use?
(Amount of open space; dislocation
of existing residences and businesses; land use - transportation compatibility
index[8]; community quality of life measure[9])
Environmental: How does the
transportation system affect important environmental features? (Impacts
on sensitive areas [wetlands, parklands, historic areas, archaeological sites);
noise exposure index[10]])
Economic: How does the
transportation system support the economic health of the region? (Narrative discussion of economic-activity
supporting or constraining features of transportation system)
[1] Maximum acceptable time difference is approximately 15 minutes; up to 20 minutes for longer trips.
[2] While choice of mode for freight movement is largely decided by cost factors, availability of alternative modes is a measure of access.
[3] Person hours used for all values except for truck traffic, for which vehicle hours are more relevant.
[4] Reserve capacity is defined by corridor and is modally-weighted.
[5] Maximum value derived from access value (see footnote 1), further constrained by non-auto system capacity (bus capacity, etc.).
[6] Reasonable alternatives for personal travel during closure/disruption of a highway include transit (on alternative routes) or parallel highways; reasonable alternatives for freight are primarily parallel highways. Modal alternatives for freight are captured under access.
[7] Risk is defined as the "opportunity cost" of over or under-investing in a capital project if projections prove incorrect. Examples include loss of needed rights-of-way; building capacity predicated on unrealized future demand; or construction of under-sized facilities.
[8] Index captures the level of traffic intrusion in residential areas, defined as daily traffic divided by average residential driveway spacing. Compatibility between arterial and local access function is defined as daily traffic divided by average commercial driveway spacing.
[9] Measure is a combination of quantitative and qualitative factors that reflect community quality of life by subregion (central cities, inner suburbs, outer suburbs, small cities and villages, rural areas). See Technical Report series for more information.
[10] Index is
the product of dBa and number of households in areas in which dBa
exceeds accepted thresholds.