A Better Way to Measure Traffic, Part Three

In Part Two, we listed four corridors with high volumes and low speeds. Today, we list four corridors with modest volumes and low speeds. While these corridors perform differently than the ones we listed yesterday, they may be even more clogged. Several of these roadways contain chains of gridlocked intersections that collectively cut down on auto movement.

The Worst Modest Volume, Low Speed Corridors

These corridors have very low speeds but do not have critical lane volumes that exceed policy area standards (at least not in the evening). The relatively modest volumes combined with the crawling speeds suggest that cars have an extremely difficult time squeezing through these gridlocked areas.

Colesville Road, 16th Street to Spring Street

Test Run #1
5/23/07 at 5:06 PM, Eastbound
0.77 Miles in 7.87 Minutes, 5.9 MPH

Test Run #2
5/23/07 at 7:34 PM, Eastbound
0.66 Miles in 5.57 Minutes, 7.1 MPH

PM Critical Lane Volumes
Colesville at East-West Highway: 1061 (Recorded on 6/2/04)
Colesville at Georgia: 1049 (Recorded on 9/26/06)
Colesville at Spring: 1248 (Recorded on 9/20/06)

Notes: This corridor is located in Downtown Silver Spring and runs past the Metro Station.

Frederick Road, Chestnut Street to Montgomery Village Avenue

Test Run #1
5/15/07 at 5:47 PM, Northbound
0.54 Miles in 4.97 Minutes, 6.5 MPH

Test Run #2
5/15/07 at 6:15 PM, Northbound
0.67 Miles in 5.85 Minutes, 7.1 MPH

PM Critical Lane Volumes
Frederick at Chestnut: 1204 (Recorded on 9/30/04)
Frederick at Odenhal: 1372 (Recorded on 11/10/04)
Frederick at Perry: 974 (Recorded on 3/10/04)
Frederick at Montgomery Village: 1427 (Recorded on 5/2/05)
Policy Area CLV Standard: 1450

Notes: This corridor runs near Lake Forest Mall and the I-270/Quince Orchard Road interchange.

Georgia Avenue, Prince Phillip Drive to Olney-Sandy Spring Road

Test Run
5/30/07 at 5:32 PM, Northbound
0.97 Miles in 5.17 Minutes, 11.3 MPH

PM Critical Lane Volumes
Georgia at Prince Phillip: 1145 (Recorded on 3/6/07)
Georgia at King William: 1095 (Recorded on 12/9/03)
Georgia at Olney-Sandy Spring: 1251 (Recorded on 3/15/07)
Policy Area CLV Standard: 1450

Notes: This corridor is just south of the Olney commercial district.

Georgia Avenue, Spring Street to Dennis Avenue

Test Run #1
6/4/07 at 5:15 PM, Northbound
0.46 Miles in 8.32 Minutes, 3.3 MPH

Test Run #2
6/4/07 at 5:15 PM, Northbound
1.46 Miles in 6.67 Minutes, 13.1 MPH

PM Critical Lane Volumes
Georgia at Spring: 1080 (Recorded on 11/17/05)
Georgia at Seminary: 1374 (Recorded on 4/7/05)
Georgia at Beltway: 1206 (Recorded on 11/20/03)
Georgia at Forest Glen: 1377 (Recorded on 6/6/07)
Georgia at Dennis: 1437 (Recorded on 6/7/07)
Policy Area CLV Standard: 1600

Notes: This corridor includes Montgomery Hills, the Beltway/Georgia Avenue interchange and the Intersection of Death. The Planning Department’s staff witnesses this congestion every day because their headquarters is at the southern tip of the corridor. A redesign of Georgia Avenue between 16th Street and Forest Glen Road is the top county priority for state projects requiring planning. The state announced it would undertake planning for this corridor back in January.

These four corridors, as well as the four listed yesterday, present the most urgent and intractable traffic problems in Montgomery County. The Planning Department should be able to dig into these corridors in great detail if they adopt the measurement system that I recommended in Part One. Some of the questions that need to be answered are:

1. Is some level of congestion actually desirable? Heavily populated down-county areas like Bethesda and Silver Spring have large numbers of pedestrians. Policies that speed cars may cause increases in pedestrian accidents.

2. Are there any transit improvements that could ease the congestion? Five of the eight corridors (Wisconsin, Rockville Pike, Colesville, and two on Georgia) are already near Metro stations. Could some of the traffic be headed to areas beyond Metro’s reach? If it is, Metro extensions (including bus rapid transit) may be warranted. US-29 would be a particularly good candidate.

3. What does this information mean for the Purple Line? Four of the eight corridors (Wisconsin, Connecticut, Colesville and Georgia) would be along or close to the route for the Purple Line. But the congestion measurements we have now apply to north-south traffic during evening rush. Would the Purple Line really be effective in alleviating north-south traffic? Perhaps a GPS test drive should be held on East-West Highway, which is the major auto connection between Bethesda and Silver Spring. If its congestion level matches that found in these eight bad corridors, that would strengthen the case for a direct transit connection.

Dear readers, never in the history of Maryland blogdom (or as far as I know, the mainstream media) has anyone suggested such a radical redesign of our traffic measurement system as I have. The Planning Department’s over-reliance on critical lane volumes without context has produced an incoherent, unreliable measurement system that is plagued with bad data. If we cannot correctly diagnose our problems, we will never arrive at a solution. Our current economic downturn will not last forever. When it ends, development will resume and traffic will get even worse. High gas prices will increase our cost of sitting in congestion. The time to re-evaluate, improve and plan for the inevitable is now.