Residents have expressed anger about plans to increase the number of bus stops on a route, because they say it will provide more places for drivers to urinate.
The proposals are being made for the U7 route, which runs from Uxbridge to the Charville Lane estate, and would bring additional stops to Charville Lane and Hewens Road in Hayes.
But residents say the area does not need them, and they already see both male and female drivers urinating at nearby stops.
They are also concerned because they feel Charville Lane is too narrow for buses and it will lead to more accidents on an already dangerous road.
Nicola Brightman, of Charville Lane, said: "Bus drivers have been seen peeing at the existing bus stop in Hopner Road, and if we have new stops they will be doing that there too. Obviously people don't want their children to be looking at that sort of thing.
"If the proposals go ahead it will mean paving over Green Belt land, and this is such a lovely rural bit of Hayes."
Jonathan Hayles, of Turner Close, Hayes, said: "The proposed locations of the bus stops are sheer madness. It's right near a hazardous, busy corner which gets heavily congested at school opening and closing times.
"A previous extended bus service was withdrawn through lack of interest, and that's because the bus services in Charville Lane and on the Uxbridge Road already serve the area very well."
Councillor Peter Curling (Lab), who represents Charville ward, said: "The residents who have contacted me have said they had not been given any consultation about this.
"They are concerned because some bus drivers are using the bushes opposite their homes as a toilet.
"I've even been told a resident has seen a female bus driver urinating while standing on the entrance platform of her bus."
A Transport for London spokesperson said: "The changes to route U7 are being introduced next spring in response to requests from local residents.
"The rerouted U7 will provide residents of the Charville Lane Estate with a quicker link to Hillingdon Hospital and Uxbridge, and a new direct bus to the Hayes Grapes area. It will also serve Hewens Road and Pole Hill Road.
"We have worked with the local council and the police to identify bus stop locations, taking into account safety, convenience for passengers and the impact on the local area."