Citroen DS Taxi - 2015 (Back to the Future II - 1989)
By 2015, taxicabs, like most vehicles, were able to fly, which rendered transportation much quicker than when they were road cars. However, the fares were much more expensive compared to the previous century.
The DeLorean time machine nearly collided with a taxicab when it departed from Lyon Estates in 1985 and appeared in the wrong lane of Skyway C25 on October 21, 2015, facing oncoming traffic.
On the same day, Biff Tannen followed the DeLorean, with Doc and Marty aboard, to Hilldale in Cab B25 from the Luxor Cab Company. Fred, the cab driver, had an intelligent parrot named Priscilla that could read the amount of the fare.
The cab had its own entertainment system consisting of "200 local channel stereo, mobile phone, food, beverage and snack dispensing systems".  Biff may have made use of this facility to pass the time while the vehicle was stuck on the jammed Skyway C25.
[Text from Backtothe future.wikia.com]
The Citroen DS Taxi is the very first vehicle seen in the year 2015 - a remarkable 60 years after the original launch of the DS road car. The DS Taxi still looks more modern than a majority of the taxis on the road today - though the Toyota Prius probably comes closest.
Old Biff uses the DS Taxi to get about in Hill Valley through the 2015-era part of the movie.
This Lego miniland scale Citroen DS Taxi - 2015 (Back to the Future II) has been created for Flickr LUGNuts' 96th Build Challenge - The 8th Birthday, titled - 'Happy Crazy Eight Birthday, LUGNuts' - where all previous build challenges are available to build to. This model is built to the LUGNuts 6th build challenge, - "Your Claim to Fame" - a challenge encouragingthe builder to create an iconic model with some level of popular culture reference (to ensure lots of interweb exposure) - in this case, this model is created and loaded to the interweb in the lead up to October 21st 2015 - the day that Marty and Doc Brown arrive in 2015 from their original timeline in 1985.