Enhanced safety.  According to the National Highway Traffic Safety Administration (NHSTA), 37,133 people lost their lives in motor vehicle crashes in 2017.  NHTSA Deputy Administrator Heidi R. King stated that “dangerous actions such as speeding, distracted driving and driving under the influence are still putting many Americans, their families and those they share the road with at risk.”  Many believe that autonomous vehicles could reduce fatalities caused by human error and/or carelessness.
Efficiency and productivity.  Autonomous vehicles could enhance efficiency, particularly if it promotes ride sharing.  Not as many cars would sit idle in parking garages and lots with a transition to transportation on demand. 
Environmental benefits.  Autonomous vehicles, particularly electric-powered, could reduce emissions.  Akin to cruise control, sensors and software aboard the vehicle could result in more consistent and appropriate distances between automobiles and vehicle speed, thus lowering emissions released from frequent braking and acceleration and improved fuel economy.
Enhanced mobility.  For those with restricted mobility as a result of age or disability, fully automated cars could enhance transportation options and improve access to employment opportunities and health care.

Job losses.  According to the American Trucking Association, there were 3.5 million truck drivers employed in the United States in 2018.  Autonomous vehicles could result in a loss of those jobs. 
Technology blind spots.   Many believe the systems used to power driver-less cars are far too nascent, and many are skeptical the technology is advanced enough to correctly anticipate every situation without human intervention fearing a mishap like the recent Boeing 737 MAX crashes.  In March 2019, AAA announced the results of its annual automated vehicle survey that found that 71% of people are afraid to ride in fully self-driving vehicles.
Obsolescence.  According to the Bureau of Transportation Statistics, the average age of passenger cars and light trucks in operation in the United States has risen from 8.4 years in 1995 to 11.6 years in 2016.  Much like an I-Phone, changes in technology and software are likely to accelerate vehicle obsolescence and require more frequent purchases of automobiles, even for ride-share services.  The automakers and tech companies may just be counting on it.
More than just the vehicle.   While much attention is focused on the vehicle, a study by Deloitte expands the discussion to an entire “mobility ecosystem” where investments in infrastructure and technology are needed to facilitate autonomous vehicles.  Telecommunications companies, such as AT&T, may provide connectivity technology to assist driver-less vehicles to make real-time decisions based on information beyond the sensors aboard the vehicle. 

It’s a long road. A CNBC article cited Michelle Avary, head of autonomous mobility at the World Economic Forum, as suggesting the industry needs to overcome two big challenges, including technology and business models that can make money.  While driverless vehicles could become mainstream at some point, it is likely to take many years before it becomes a reality on mass scale.  Like most technological advancements, it is likely that consumers may grow comfortable with advancements over time, much like the incorporation of parking assist and collision warning systems.  However, rather than rushing to advance autonomous driving technology, consumers may prefer that automakers devote more immediate investment and resources toward advancing electric and hybrid vehicles, including battery technology that improves range, extends life and lower cost.
Sources:
Statement by Donald J. Trump, Twitter, Donald J. Trump, March 12, 2019
U.S. DOT Announces 2017 Roadway Fatalities Down, U.S. Department of Transportation, National Highway Traffic Safety Administration Press Release, October 3, 2018
Self-Driving Cars:  The Impact on People with Disabilities, Ruderman Family Foundation, Henry Claypool, Amitai Bin-Nun, Ph.D., Jeffrey Gerlach, January 2017
Millions of Professional Drivers Will Be Replaced by Self-Driving Vehicles, NBCNEWS.com, Paul A. Eisenstein, November 5, 2017
News and Information Reports, Industry Data, American Trucking Association, 2019
Three in Four Americans Remain Afraid of Fully Self-Driving Vehicles, AAA, AAA Press Release, March 14, 2019
Average Age of Automobiles and Trucks in Operation in the United States, Bureau of Transportation Statistics, 2019
Forces of change:  The future of mobility, Deloitte Insights, Scott Corwin and Derek M. Pankratz, 2017
AT&T is Leading the Way on Connecting the Cars of Today and Tomorrow, ATT.com, Chris Penrose-President, loT Solutions, AT&T, October 31, 2018
Self-driving cars face two important challenges, says World Economic Forum executive, CNBC, Saheli Roy Choudhury, July 1, 2019
Two Big Challenges Face Autonomous Vehicle Industry, The Detroit Bureau, Paul A. Eisenstein, July 1, 2019