23 CFR § 490.713 - Calculation of Traffic Congestion measures.

(a) The performance measures in § 490.707 shall be computed in accordance with this section by State DOTs and MPOs to carry out CMAQ traffic congestion performance-related requirements of this part and by FHWA to report on traffic congestion performance.

(b) The performance measure for CMAQ traffic congestion specified in § 490.707, Annual Hours of Peak Hour Excessive Delay Per Capita (the PHED measure), shall be computed to the nearest tenth, and by summing the PHED metrics of all reporting segments in each of the urbanized area, specified in § 490.703, and dividing it by the population of the urbanized area to produce the PHED measure. The equation for calculating the PHED measure is as follows:

$\begin{array}{c}\text{Annual Hours of Peak Hour Excessive Delay per Capita}\\ =\frac{\sum _{s=1}^T{\mathrm{Total}\mathrm{Excessive}\mathrm{Delay}}_s}{\text{Total Population}}\end{array}$

Where:

Annual Hours of Peak Hour Excessive Delay per Capita = the cumulative hours of excessive delay, to the nearest tenth, experienced by all people traveling through all reporting segments during peak hours in the applicable urbanized area for the full reporting calendar year;

s = travel time reporting segment within an urbanized area, specified in § 490.703;

T = total number of travel time reporting segments in the applicable urbanized area;

Total Population = total hours of excessive delay in § 490.711(e) for all people traveling through travel time reporting segment “s” during a calendar year (as defined in § 490.711(f)); and

Total Population = the total population in the applicable urbanized area from the most recent annual population published by the U.S. Census at the time that the State Biennial Performance Period Report is due to FHWA.

(c) Calculation for the PHED measure, described in paragraph (b) of this section, and target establishment for the measure shall be phased-in under the requirements in § 490.105(e)(8)(vi) and (f)(5)(vi).

(d) The performance measure for CMAQ traffic congestion specified in § 490.707(b), Percent of Non-SOV Travel, shall be computed as specified in paragraphs (d)(1) through (3) of this section corresponding to the method reported by the State DOT to collect travel data for the applicable area under § 490.709(f)(2).

(1) Method A—American Community Survey. The Percent of Non-SOV Travel shall be calculated to the nearest tenth of a percent using the following formula:

Percent of Non-SOV Travel = 100% − % SOV

Where:

Percent of Non-SOV Travel = percent of commuting working population, to the nearest tenth of a percent, that predominantly do not commute by driving alone in a car, van, or truck, including travel avoided by telecommuting; and

% SOV = percent estimate for “Car, truck, or van—drive alone”.

(2) Method B—local survey. The Percent of Non-SOV Travel shall be calculated using the data derived from local survey results as specified in § 490.709(f)(1)(ii). The Percent of Non-SOV Travel measure shall be calculated to represent travel that is not occurring by driving alone in a motorized vehicle, including travel avoided by telecommuting, as a percentage of all surface transportation occurring in the applicable area. The Percent of Non-SOV Travel measure shall be calculated to the nearest tenth of a percent.

(3) Method C—system use measurement. The Percent of Non-SOV Travel shall be calculated to the nearest tenth of a percent from the data collected from system use measurements as specified in § 490.709(f)(1)(iii) using the general form of the following formula:

$\text{Percent of Non}-\text{SOV Travel}=100\times \left(\frac{{\mathrm{Volume}}_{\mathrm{non}-\mathrm{SOV}}}{\left({\mathrm{Volume}}_{\mathrm{non}-\mathrm{SOV}}\right)+\left({\mathrm{Volume}}_{\mathrm{SOV}}\right)}\right)$

Where:

Percent of Non-SOV Travel = percentage of travel, to the nearest tenth of a percent, that is not occurring by driving alone in a motorized vehicle, including travel avoided by telecommuting

Volumenon-SOVVolume = Annual volume of person travel occurring while driving alone in a motorized vehicle; and

VolumeSOV = Annual volume of person travel occurring on modes other than driving alone in a motorized vehicle, calculated as:

$\sum _{m=1}^t{\mathrm{Volume}}_m$

Where:

m = travel mode (modes other than driving alone in a motorized vehicle, including travel avoided by telecommuting);

Volume m = annual volume of person travel for each mode, “m”; and

t = total number of modes that are not driving alone in a motorized vehicle.