Jersey in Transition (JiT) is calling for a Park and Ride scheme to be set up in the west of the island, near the airport.
The environmental campaign group is suggesting a year-long trial.
It believes Park and Ride would reduce the number of cars on the roads by encouraging more islanders to use public transport.
It would like to see the Airport Village area, which was used as a Covid testing site, used as a parking area.
Nigel Jones from JiT thinks the facility would make a significant difference.
"I think a lot of people are not using buses because they do not have a regular bus service that comes close to their home and pick them up at the time they want.
There's a number of ways we could improve that, but one simple way to do it would be a park and ride scheme.
You drive to a place where there is a good bus service that is only a short distance from your home, then the bus takes you through all the traffic into town.
We're hoping around 100 cars could easily fit into this car park, then that would be 100 people on buses and 100 cars off the road. If that could be multiplied up, it could make a significant difference.
All we need it permission from Ports of Jersey, some co-ordination between Ports of Jersey and LibertyBus, and then some signs putting up, and that would be about it.
Then we'd just need to monitor it and see how many people use it."
If it is a success, JiT says it could be rolled out to other parts of the island.
Ports of Jersey says it has not been approached by the group about the proposal and it would need to consider how it would impact its operations.