Studies have suggested that rideshares increase traffic jams.
Now researchers are saying they also make traffic jams last longer.
According to the Massachusetts Institute of Technology, a new study found that that rideshares increased congestion by less than 1%.
But researchers found it also made that congestion last 5% longer.
The study looked at the two most popular ridesharing companies: Uber and Lyft.
Researchers point to what they call deadheading miles or miles the cars travel without a passenger.
They believe that is what is having a negative impact on traffic.