Advocates for self-driving cars love to tout the benefits the cars would bring, such as fewer accidents and less congestion. Another alleged value of being a passenger rather than a driver is more productivity—you could work rather than concentrate on driving. But most people might not spend their newfound free time in self-driving cars whittling down their to-do lists.

That’s according to a study by Michael Sivak and Brandon Schoettle at The University of Michigan’s Sustainable Worldwide Transportation program. [Michael Sivak and Brandon Schoettle, Would Self-Driving Vehicles Increase Occupant Productivity?]