More than £100m per year is spent clearing driver-generated litter
Drivers on Scotland's motorway network have been warned they could be fined for throwing litter from their cars.
Keep Scotland Beautiful (KSB) said fixed penalty notices of £50 could be issued to motorists caught on CCTV.
The anti-litter group is supporting the "Don't tip on your trip" campaign, set up by the roads maintenance firm, Amey.
During national motorway litter week, Amey will be targeting drivers in the south west of Scotland where 50 tonnes of rubbish is recovered each month.
Amey's support manager, Jim Gilmour, said litter cleared from stretches of the M8, M73, M74, M80 and M77 every year was enough to fill two public swimming pools.
"There's no escaping it on the slip roads in particular," he said.
"People slow down, put the window down and throw out the crisp packet, cigarette packet or apple cores.
"That accumulates very quickly to about 13 tonnes per week."
KSB manager, Donna Niven, said the vast amounts of litter on the motorway network were removed at considerable cost.
"If you take in the motorways, the trunk roads and all of the rural roads, it's way over £100m per year," she said.
More councils in Scotland are now using fixed penalty fines of £50 for people caught littering on the streets.
Ms Niven said this approach was now being used to tackle the problem on the roads.
"Big Brother is watching us everywhere today. There are CCTV cameras all over the place," she said.
"We can actually track the drivers and the registration numbers and send that fixed penalty notice through the post to your door."
National motorway litter week, which began on Monday, is supported by the RAC Foundation, Transport Scotland and Keep Scotland Beautiful.