CDOT Performance Data Business Plan - Cambridge Systematics

CDOT Performance Data Business Plan
In addition to the issues identified in Table 3.2 a global issue is to finalize the use
of a grading scale. The following sections recommend a grading scale from A to
F that could be applied consistently to all measures except for number of
fatalities. Other options identified throughout the course of this project include a
variable grading scale that reflects differences in the measures (for example, an A
for bridges might represent a higher percent of good/fair than an A for
pavements), and the assignment of grades based on achievement of a long-term
target value.
The following sections describe the recommended measures. Details related to
data and calculations are contained in Section 3.6.
System Performance
1. Number of Fatalities (5-year moving average)
Existing Measure: Number of fatalities per 100 million vehicle miles traveled
is currently tracked and reported by CDOT.
Recommendation: Recommended modification to this measure is to report
the number of fatalities rather than the fatality rate, and report a five-year
moving average rather than a single year.
Current Value: 1.01 fatalities per 100 million VMT
Value Based on Recommendation: The current annual average of fatalities on
state highways from 2005 to 2009 is approximately 542 (based on NHTSA
Fatality Analysis Reporting System (FARS) data).
Owner: Rahim Marandi
Required Data Item Source Owner
Fatalities by year for past five years TRAFDA Safety and Traffic Engineering
Unit of Measure: Count
Calculation:
Where:
K = number of fatalities
n = year of calculation
Update Frequency:
Annually
Additional Notes: A random element occurs in the timing and location of
serious crashes. Therefore, the annual number of fatalities may fluctuate a great
deal from one year to the next. Relying on a moving average number of fatalities
over a five-year period provides a more stable picture of crash occurrence, and
3-8 Cambridge Systematics, Inc.