Early interest in an autonomous rideshare service in Irvine was so great, organizers decided not to kick off the start of their three-month pilot program with a big promotional splash on Monday, Nov. 4.

BotRide is a free service from carmaker Hyundai and two other companies – Pony.ai makes the self-driving technology and Via created the app for users. It moved into more widespread testing Monday, after UC Irvine students served as a rider pool providing early feedback.

The Irvine program is one of four the state is allowing to carry passengers in self-driving vehicles, and only one of them (run by Google offshoot Waymo) can do so without a human in the driver’s seat for safety. None is permitted to charge for rides.

Hyundai is using two people in the front of each vehicle – one who can take over the brakes or steering wheel if needed, and one to check driving conditions and surroundings against what the car’s sensors and cameras are picking up.

Daniel Han, advanced product strategy manager for Hyundai Motor USA, said word of the program spread until several hundred people were signed up for the bigger pilot program. Over the past couple weeks, about 50 UCI students helped test the service, which picks up and drops off riders at 13 spots around Irvine.

“Ultimately the power of free is pretty strong. This is a free ride that people have whenever they want” during service hours, Han said. The self-driving electric SUVs operate from 8 a.m. to 8 p.m. weekdays and 9 a.m. to 6 p.m. Saturdays.

The rideshare program is available to Irvine residents who register through the website at botride/ridewithvia.com. Han said they’ll add new blocks of riders about once a week until they reach a yet-to-be-determined capacity.

Among what Hyundai officials are hoping to learn is whether QR codes are an effective way to identify and validate passengers, and the optimal number of vehicles and destinations at which the cars aren’t circling around empty, but riders don’t have to wait too long to get picked up, Han said.

Han said the Irvine test is “our first step in understanding what a future of autonomous vehicles offering rides to people could look like,” and officials are already thinking about a next phase but are still working on the details.