Uber has confirmed that it is now testing bus-style 'Smart Routes' in San Francisco which allow drivers to both pick up and drop off passengers along a specific route.

The new UberPool feature overlays a green line on the app's map which indicates a nearby Smart Route. Anyone who sets their pickup point somewhere along a Smart Route, rather than being picked up from their door, will be discounted $1 or more off the normal UberPool price; the idea being that a little convenience is traded for a cheaper fare.

We have begun testing a new feature to streamline the uberPOOL experience for both riders and drivers. This experimental feature, called 'Smart Routes', aims to simplify pick-ups by encouraging riders to request a ride along specific routes in San Francisco. Smart Routes is part of our ongoing efforts to increase the efficiency of driver-partners' time spent on the road while helping riders save time and money.

Right now, the company is experimenting with only two San Francisco routes: Fillmore Street between Haight and Bay, and Valencia Street between 15th and 26th.

As well as the discounted fare for passengers, the new service also offers some advantages for Uber drivers; the company claims the feature will maximize the efficiency of the drivers' time by increasing the number of passengers they collect per hour and allow for fewer detours. This means that even with the reduced fares, a Smart Routes driver should theoretically be able to make more money than a traditional Uber driver.

The UberPool service, introduced last year, lets Uber users split the cost of their journey by sharing a ride with a stranger who is travelling a similar route. This cuts a normal Uber fare by 50%, meaning that when combined with the discounted Smart Routes offers, UberPool could become cheaper than public transport in the San Francisco area.

Uber has not commented on whether Smart Routes is part of the "perpetual rides" idea that CEO Travis Kalanick discussed last year. Speaking about the concept at the Digital-Life-Design conference in Europe last October, the company co-founder said: "It's the perpetual trip, the trip that never ends. The driver picks one passenger up, picks another passenger up, drops off the first passenger, but then picks up passenger number three and drops off passenger number two."