Performance Measures

The CMP is multimodal; it monitors limited-access and arterial roadways, interchanges, intersections, park-and-ride lots, bicycle parking at transit stations, pedestrian and bicycle transportation (as part of intersection monitoring), carpool and vanpool park-and-ride facilities, transit schedule adherence, and transit vehicle capacity.

The MPO staff collects data by facility type. For additional analysis, the CMP acquires data from other sources, such as the U.S. Census Bureau, the MBTA, and MassDOT. The data are matched to performance measures, many of which are associated with thresholds. Depending on the situation, selected performance measures are mapped, tabulated, or used as input for level-of-service analysis in order to estimate performance based on level of service (LOS), utilization rates, speed indices, crash rates, and other measures. Based on performance measures, congested locations are prioritized for recommendations for planning studies in the UPWP (Unified Planning Work Program), for project evaluation and prioritizing in the TIP (Transportation Improvement Program), and for the Needs Assessment in the LRTP (Long-Range Transportation Plan).

The following performance measures are used by the CMP, organized by facility type.

Roadways, Intersections, and Interchanges

HOV Lanes and Parallel General-Purpose Lanes

Transit Service

Park-and-Ride Facilities (MBTA and MassDOT Facilities)

The connections between performance measures, CMP objectives, and MPO policies are shown in Table 1-1, and the data sources for the performance measures are listed in Table 3-1.


 

TABLE 3-1

CMP Performance Measures and Data Sources

 

Facility

 

Performance Measure

 

Data Source

Roadways, Intersections, and Interchanges

 

Average observed travel speed

 

CTPS travel speed runs

 

Speed index

 

CTPS travel speed runs

 

Delay

 

CTPS travel speed runs

 

Traffic volumes (all modes)

 

MassDOT and CTPS intersection site visits

 

Volume/capacity (V/C) ratio

 

CTPS intersection site visits

 

Level of service

 

CTPS intersection site visits

 

Approach speed

 

CTPS travel speed runs

 

Approach delay

 

CTPS intersection site visits

 

Number of crashes

 

MassDOT crash data

 

Crash rate

 

MassDOT crash data

 

Vehicle occupancy

 

CTPS occupancy and traffic counts

HOV Lanes and Parallel General-Purpose Lanes

 

Travel time savings

 

CTPS travel speed runs

 

Vehicle occupancy

 

CTPS occupancy and traffic counts

Transit Vehicles

 

On-time performance

 

CTPS ride checks, MBTA data

 

Passenger crowding

 

CTPS ride checks, MBTA data

Park-and-Ride Facilities (MBTA and MassDOT)

 

Lot capacity and utilization

 

CTPS park-and-ride site visits, MassDOT data

 

Time a lot fills up

 

CTPS park-and-ride site visits

 

Bicycle parking capacity and utilization

 

CTPS park-and-ride site visits

 

 

 

Congestion Thresholds

Many CMP performance measures have associated thresholds that are used to identify when congestion is occurring, or to otherwise distinguish between undesirable outcomes and desirable outcomes. If the thresholds are surpassed, the transportation facility may be identified as a congested corridor

These thresholds are listed in Table 3-2.

TABLE 3-2
Congestion Thresholds

Performance Measure

Threshold

Indicators of congestion:

< 50 mph (limited-access roadways)

Average observed travel speed

≤ 21 mph (partially limited-access arterials)

≤ 14 mph (other arterials)

Speed index

< 0.70 indicates congestion

Delay

≥ 55 seconds (arterials) indicates congestion

Traffic volumes (all modes)

Depends on functional class roadway capacity

Volume/capacity (V/C) ratio

> 1.0 indicates congestion

Level of service

E or F indicates congestion

Approach speed

Varies

Approach delay (interchanges)

Varies

Number of crashes

No threshold

Crash rate

MassDOT Highway Division District average. Anything higher indicates problem areas

HOV travel time savings

One minute per mile is the minimum acceptable benefit

Vehicle occupancy

No threshold

On-time performance

Varies (see page 4-8 for more information)

Passenger crowding

Varies (see Table 4-9)

Park-and-ride lot utilization

Full: ≥ 85%

Underutilized: < 50%

The time a lot fills up

 

There is insufficient parking capacity if the lot fills to 100% before the departure time of the last AM peak-period train.

Bicycle parking capacity and utilization

Full: ≥ 85%

Underutilized: < 50%

 

1   Transportation Research Board. Highway Capacity Manual. Washington, D.C., TRB, 2010.