Simple Reaction Time Did Not Represent Every Level of Cannabis-Related Driving Skill

A driving review organized performance into operational, tactical and strategic levels. A result on a simple cognitive task could not automatically describe the higher-level decisions required in traffic.

The framework distinguished task demands

Pearlson and colleagues describe basic perception and steering, more integrated tasks such as following a car, and strategic decisions such as overtaking. Driving emerges from their coordination. The framework is a way to organize evidence, rather than a validated score assigning every driver one position on a scale.

One normal measure leaves other questions open

A simple reaction-time result does not directly establish divided attention, coordination with another vehicle or safe passing decisions. The reverse is also true: a difference on one cognitive task does not prove that every driving maneuver failed. The outcome must match the function being discussed.

A practical interpretation follows the disputed demand

For a driving opinion, identify the actual demand and the evidence assessing it. A laboratory finding may be relevant without being a complete surrogate for driving. The review supports using several complementary levels of assessment rather than treating any isolated task as the whole activity. Its conceptual hierarchy does not establish a THC concentration threshold or prove how a particular driver performed during a collision.

Related analysis: the review’s broader findings and limitations.

Research cited

This analysis draws on the supplied review: Pearlson, Stevens and D’Souza (2021). Cannabis and Driving. Frontiers in Psychiatry.