The course for this year's Robin Hood marathon could be changed because organisers are concerned the streets of Nottingham city centre are too narrow.
The race attracted more than 13,000 participants last year
Currently the course goes through the city centre and then on to Lenton Lane, where participants are asked to be patient if there are delays.
The new route would take participants through the grounds of the University of Nottingham for the first time.
Organisers are still awaiting final approval for the new route.
Chris Humner, one of the people behind the race, said: "We've had to change the route because the event's been so successful that the roads we use are no longer large enough to take the event.
"So what we'd like to do is put it on some wider roads."
He said they then intended to try and get the event televised in 2007.
The Robin Hood Marathon will take place on 10 September 2006.
The race attracted more than 13,000 participants in 2005.