Los Alamos County plans centerline rumble strips on New Mexico 502 after fatal crash

Jennifer Morrow, a public works engineer with Los Alamos County, told the Transportation Board that county staff are preparing safety improvements on New Mexico 502 after a history of crashes and a fatality.

"In September 2024 there was a fatality," Morrow said, and she described a road safety audit (RSA) conducted by Los Alamos National Laboratory that covers the corridor from Airport Road east to just past Eastgate Road. She said the county is proceeding with two countermeasures: restriping at Camino Entrada and Bridal and installing centerline rumble strips along the corridor. Morrow said the passing lane in front of the airport will be removed and replaced with a continuous double-yellow center line, with designated gaps to preserve left-turn movements.

Morrow described the rumble strip design and benefits: "a rumble strip is a ground out section of asphalt that is 7 inches by 16 inches and a half inch deep," and she said studies show rumble strips "can reduce head on collisions by up to 45 percent." When asked for a source, Morrow said she obtained the statistic from the Federal Highway Administration website and apologized for not including the citation in the packet. She also said the county has a letter of support from the New Mexico Department of Transportation.

County staff warned that contractor options are limited: "there is only 1 rumble strip machine in all of New Mexico," Morrow said, and contractors have quoted the county; she added the project should take about two days in the field (one day to mobilize equipment and one day to install the rumble strip and replace centerline striping).

Board members raised operational questions and alternative options. One member urged stronger enforcement of speed and cellphone use, saying enforcement can be highly effective; a county staffer replied that existing rumble strips on Main Hill have not affected snow removal operations and that Los Alamos Police Department conducts enforcement during peak hours. Staff also said the RSA considered a roundabout at the Camino Entrada intersection but noted concerns about traffic backup on the downhill approach during inclement weather, so a roundabout would require further study.

Next steps, according to Morrow, include finalizing a contract with the selected contractor and scheduling mobilization; staff said the county and NMDOT will continue coordination and that the county's crash data (2015–2023) and RSA findings informed the proposed measures.

The board did not take a formal vote on the NM 502 improvement package at the meeting; staff will return with follow-up materials, including the FHWA citation and project schedule.