The buffer index represents the extra time (buffer) most travelers add to their average travel time when planning trips. This is the extra time between the average travel time and near-worst case travel time (95th percentile). The buffer index is stated as a percentage of the average travel time. Average buffer index or buffer time can be calculated using miles traveled as a weighting factor. Buffer time = 95th percentile travel time (min) – average travel time (min). (Performance Measure*)

Associated Objectives

Decrease the buffer index for (specific travel routes) by X percent over the next Y years.
Decrease the average buffer index for (multiple routes or trips) by X percent over Y years.
Reduce the average buffer time needed to arrive on-time for 95 percent of trips on (specified routes) by X minutes over Y years.

Service Packages that Support the Performance Measure

ATIS01-Broadcast Traveler Information
ATIS02-Interactive Traveler Information
ATIS04-Dynamic Route Guidance
ATIS09-In Vehicle Signing
ATIS10-Short Range Communications Traveler Information
ATMS03-Traffic Signal Control
ATMS04-Traffic Metering
ATMS06-Traffic Information Dissemination
ATMS08-Traffic Incident Management System
ATMS22-Variable Speed Limits
ATMS23-Dynamic Lane Management and Shoulder Use
MC06-Winter Maintenance
MC08-Work Zone Management
MC10-Maintenance and Construction Activity Coordination

Associated Goals

Increase operational efficiency and reliability of the transportation system

Planning Factors

G. Promote efficient system management and operation;

Source

Planning for Operations Desk Reference