Average Vehicle Occupancy (AVO) as a Key Performance Metric

November 7, 2019

The Energy Efficiency 2019 report, published this week by the International Energy Agency (IEA), warns that average vehicle occupancy rates are falling - mitigating the energy benefits that come with more efficient vehicles. Coupled with the declaration this week of a “climate emergency” by 11,000 scientists, it’s clear that average vehicle occupancy (AVO) is a metric deserving of greater attention.

Most of our cities have an average vehicle occupancy of 1.1 at peak travel periods. Research shows that even a small decrease in traffic volume (2-5%) can have a huge impact (25%-27%) on traffic congestion. A small increase in peak-time vehicle occupancy from 1.1 to 1.2 or 1.3 would eliminate traffic gridlock on our most congested corridors.

Armed with this knowledge, policy makers have a clear, practical and actionable performance metric that can help to fight congestion, local air pollution and climate change. However, planners rarely even attempt to measure AVO, yet alone offer high-occupancy vehicle (HOV) incentives such as toll discounts, dedicated lanes or preferential parking. 

That’s about to change. The catalyst for that change is not just that reputable international organizations like the IEA are sounding the alarm about AVO, or the impending arrival of zero-occupancy vehicles, but also a predicted explosion in vehicle miles traveled (VMT), as car travel becomes more affordable. Against this backdrop, legacy metrics such as vehicle throughput or VMT are inadequate. The time for AVO as a key performance metric has arrived.

Energy policy in an age of climate emergency requires urgent, innovative and practical steps to be taken to reduce the negative energy impact of road transportation. With AVO now declining, an obvious first step is to reverse course by measuring occupancy and designing policies that foster HOV travel. It doesn’t require new car technologies or major infrastructural investment - simply a new vision for how we inspire and enable transportation behavior in our communities.