Traffic, pollution staging a comeback in Valley

‘Normal’ could mean longer commutes, worse air quality

Posted 5/28/20

Everyone from cable news pundits to neighborhood soccer moms are cheering on economic recovery and a return to normal after months of changes and challenges in the wake of the novel coronavirus …

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Traffic, pollution staging a comeback in Valley

‘Normal’ could mean longer commutes, worse air quality


Everyone from cable news pundits to neighborhood soccer moms are cheering on economic recovery and a return to normal after months of changes and challenges in the wake of the novel coronavirus pandemic.

But while many hope for a jobs market recovery, few Valley residents are likely as eager to see a return to normal traffic conditions and pollution levels.

Based on data compiled by travel time analytics company INRIX, the Maricopa County Association of Governments by early April was already reporting remarkably lower rates of traffic congestion and pollution — only days after Gov. Doug Ducey’s March 30 executive order calling on Arizonans to “Stay Home, Stay Healthy, Stay Connected.”

Traffic congestion, freeway commute times and toxic air pollution all fell dramatically as commuters adjusted to new post-COVID-19 lifestyles.

Eric Anderson, executive director at MAG, explained the impact of social distancing on roadway traffic in an April 10 report published in the Daily Independent.

“COVID-19 began affecting travel behavior in our region roughly around the second week of March,” Mr. Anderson stated. “As nonessential workers began telecommuting, schools closed, and people began staying home and off the roads, the overall traffic volume in the region has now been reduced by one-third.”

But seven weeks later — following the May 15 expiration of Mr. Ducey’s executive order — conditions on Valley roads appear headed back toward normal, while measurable pollutants in Arizona’s air may be rebounding as well.

Traffic recovering

By early April, overall traffic volume across the Valley had fallen to 63% of normal. Since dipping to that low point, by mid-May, the volume has steadily recovered to 81% of normal, according to MAG’s analysis.

With fewer cars on the road, traffic congestion fell by more than half by early April; but as of May 22, freeway delay times had returned to 66% of normal. And passenger car traffic, after dropping significantly, has now recovered to between 72% and 95% of normal conditions in some areas.

Whether the benefits of lower traffic volume — spurred by daily trip reductions and the work-from-home trend — will continue or return to previous levels remains unclear, Mr. Anderson said.

“It is too early to tell. The events have demonstrated that telecommuting and video meetings can work in many occasions. In addition, the increased reliance on Internet shopping likely will continue in the future,” he stated. “Some survey findings indicate that employers who may have been reluctant to embrace telecommuting in the past now see that it can work. Likewise, some employees have reported that they have been more productive working from home since there are fewer distractions.”

If only a portion of the workforce continues telecommuting, commuters may still see better conditions on the roads than they were previously accustomed to, he said.

“Small changes in the proportion of workers telecommuting can have a significant benefit in terms of lower congestion levels,” Mr. Anderson stated. “Changes such as telecommuting, internet shopping, ride-sharing services, and the rapid changes in technology all can have major implications on travel behavior and what transportation infrastructure investments will be needed in the future.”

But while passenger traffic dipped much lower before beginning to recover, truck traffic has remained strong and even increased since the start of the ongoing COVID-19 public health crisis.

Throughout the Spring, traffic from heavy trucks for freight transportation remained consistently strong and has now exceeded normal volumes, reaching to 109% of typical capacity by this week, according to MAG’s analysis.

Better air, still

Based on satellite data, less traffic may correlate with better air quality; this was evident as commuters started staying home in March.

Processing data from the European Union’s Sentinel-5 Precursor satellite, MAG estimated a reduction in nitrogen dioxide emissions in the Valley of more 10.5% between March 1 and March 21.

Pumped into the air mainly by cars, trucks and other fuel-burning machines, nitrogen dioxide makes it harder to breath and can lead to chronic health conditions and hospitalizations, according to the U.S. Environmental Protection Agency.

“Breathing air with a high concentration of NO2 can irritate airways in the human respiratory system. Such exposures over short periods can aggravate respiratory diseases, particularly asthma, leading to respiratory symptoms (such as coughing, wheezing or difficulty breathing), hospital admissions and visits to emergency rooms,” officials state at the agency’s website:

By April 21, NO2 emissions had dropped by nearly 17%, though data through May is not available. Whether and when this type of pollution returns to previous levels is yet a matter for speculation.

Ozone, another harmful pollutant associated with vehicular traffic in dense urban areas, has also seen reductions followed by a recovery, based on data published by the Arizona Department of Environmental Quality.

Through most of March and April, ozone measurements remained beneath — and in some cases well beneath — the year-over-year averages. By late April and into May, many more days had registered above-average ozone levels.

The lowest measurement in March came in at 36, nearly 25 points below the annual average for that day. The lowest day in May registered 46 points, nearly 33 points lower than normal.

While from Feb. 21 to April 27 ozone outpaced the average on only six days, since April 29 the level has exceeded the average 16 times, with the highest reading this year coming on May 6 when the ozone topped 147, nearly double that day’s average and well above the federal standard.