The RAC wants local councils to convert underused car parks for bike use to help tackle the growing shortage of spaces for riders.
The organisation says bikes are vital to cracking city congestion - but they could be even more important if planners made more room for bike parking.
The RAC is calling for more bike parks in support of July 28's Ride To Work Day.
The organisation says: "Motorcycling is cheap, does not contribute to congestion or pollution as much as the car, and enables improved journey-time reliability.
And it points out that bike ownership has grown 200 per cent in the last 10 years - leading to twice the demand for bike parking.
"Motorcyclists are increasingly having to park in inappropriate places e.g. footways, pedestrian areas, and forecourts because local authorities are not putting the interests of motorcyclists first when considering their parking strategies."
The organisation says that In Central London, there has been a 15% increase in motorcyclists entering the congestion-charging zone since it started in 2003. But that means on a normal working day, those who commute into London on their scooters or motorbikes have to get in by 8am to secure a space.
The RAC Foundation is today calling on local authorities to take "under-utilised car-parking spaces" and convert them into extra parking for motorcycles.
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