Calling for an improved public transportation system that would enable Massachusetts residents to cut back on driving, a report out Monday says a 1 percent decrease in the growth rate of driving miles would improve overall quality of life and result in an aggregate $20.1 billion in savings by 2030.

The report, from the MASSPIRG Education Fund and Transportation for Massachusetts, says that less driving would mean fewer automobile collisions — and a corresponding drop in injuries, economic costs and lost productivity that follows them — as well as less gasoline consumed and less money spent by governments to keep roads and bridges in good condition.

Reducing the growth rate of vehicle miles traveled (VMT) by 1 percent would decrease the number predicted by state transportation officials by 575.5 million miles in 2015, and by 74.5 billion miles total over 15 years, the report says.

"There is much to gain, with even small reductions in the future number of VMT in Massachusetts," the report reads. "Even relatively small decreases in the growth in the volume of driving translates into large benefits for the people of Massachusetts."

According to the report, the reduction of 1 percentage point over the next 15 years would generate a combined savings of $2.3 billion annually. That number consists of $857 million less spent on gas, $785 million saved from the consequences of car crashes, $446 million less spent for car repairs and $224 million less on road repairs.

To cut down on the growth of miles driven, the report's authors recommend creating incentives for Massachusetts drivers to choose other modes of transportation, including walking, biking and taking public transit. The report calls on state officials to make reducing vehicle miles traveled "a major criteria" to evaluate which transportation investments should be funded and suggests improving walking and biking trails, modernizing and enhancing capacity in public transportation systems, introducing bus rapid transit, purchasing newer and more reliable buses, and improving and expanding intercity rail service.

"The goal should be to make the combination of multiple modes of transportation serve as more than the sum of their parts to make it viable for households to drive less, or to reduce the number of automobiles they own," the report says.

To pay for upgrades, the report recommends embracing revenue sources that help meet transit needs while potentially also discouraging driving, like charging a road usage fee based on miles driven. Also suggested are "pay-as-you-drive" car insurance that would link monthly fees with distance driven and low public-transit fares, with the authors writing that large fare hikes would limit mobility of low-income riders and cause riders with car access to drive more.

Slowing the driving growth rate would also yield environmental benefits, according to the study. The 1 percent reduction, the study says, would prevent an estimated 23.3 million metric tons of carbon dioxide from being released into the atmosphere from 2015 to 2030. The emissions savings, the report says, would be the equivalent of taking more than 500,000 cars off the road in the year 2030.

The study predicts that public health effects of reduced driving would include improved mental health, reduced risk of obesity, cancer, diabetes and heart disease, and reduced health care costs.