Page 82 - U4SSC KPIs Verification Manual - A guide for verifiers

Dimension Economy
Sub-Dimension Infrastructure

Category Transport
KPI Name Travel Time Index
KPI No. EC: I: T: 5A Type: Advanced Type: Sustainable

Definition / Ratio of travel time during the peak periods to travel time at free flow periods
Description

Rationale / This indicator is a measure of congestion that focuses on each trip and each mile
Interpretation / of travel. A value of 1.30 indicates that a 20-minute free-flow trip takes 26 minutes
Benchmarking during the peak.
For more focused systems of mixed freeway and arterial facilities (no local streets)
a TTI of under 2.5 is roughly indicative of generally uncongested conditions and
good signal coordination.
For a system of solely unsignalized facilities (freeways, highways, 2-lane rural roads),
a TTI of over 1.4 is indicative of the facility being relied on in excess of its capacity
over the entire length of the analysis period.
The following should be taken into consideration for this indicator:
• TTI <= 1.5 is “Good”;
• TTI between 1.5 and 2.5 is “Potentially Acceptable”; and
• TTIs > 2.5 is “Less Desirable”.

Source(s) NOTE – US Department of Transportation. Traffic Analysis Toolbox Volume VI:
Definition, Interpretation, and Calculation of Traffic Analysis Tools Measures
of Effectiveness. Retrieved from <https:// ops .fhwa .dot .gov/ publications/
fhwahop08054/ sect6 .htm>

Methodology Calculate as:
Numerator: Travel time during peak periods (min).
Denominator: Travel time during free-flow periods (min).
Unit Ratio

Data Sources Data can be obtained from local or national transportation authorities.
/ Relevant
Databases
SDG SDG Target 11.2: By 2030, provide access to safe, affordable, accessible and
Reference(s) sustainable transport systems for all, improving road safety, notably by expanding
public transport, with special attention to the needs of those in vulnerable
situations, women, children, persons with disabilities and older persons.
Verification Check data source.
Guidance
DATA VALUES:
Re-check if data values for small cities are more than 1.4.
Re-check for larger cities if data values are more than 1.8.

72 U4SSC KPIs Verification Manual-A guide for verifiers