Well as a resident of Central Glasgow, where barely 30% of households own a car, who has live there for 32 years, 24 years at the same address, I can report from observations that the main roads parallel to M8 (North Street/Newton Street) are only gridlocked for less than 4 hours/day, and largely deserted for much of the rest of the time. This being due to the fact that drivers (largely with free workplace parking?) all try to arrive or leave some 30,000 parking spaces (paid for & free) at the same times
I was temporarily staying with a view of the M8 (Woodside Viaduct) for 5 months and at night the traffic count passing the view - both directions - was sometimes less than 1 VEHICLE
per MINUTE
On the A82 parking restrictions are not enforced because the plates have been 'removed' and so we've had one car (a 3 year old Ford Focus) lying for 6 months with a cracked windscreen and a flat tyre, on a single yellow line. Its now reappeared with a repaired tyre and windscreen and often sits for days without moving. Local intelligence suggest that the owner lives further West, but parks here because they don't have parking permit for the area they live in. It would be in interesting exercise to examine this and the owners of cars that are regularly blocking access to the 4.5m wide lane for the 3.5m width required for fire appliance access, and refuse collection trucks, including some that have not moved since 2016 and are SORN wrecks, slowly falling apart. They 'park here because they currently dodge paying for parking, and to secure that space one individual was leaving Dunblane at around 06.30 to arrive in Glasgow at 07.30, eat breakfast in the car, dump the rubbish in our garden, and walk in to work for 09.00, when he could have caught a train around 08.00, and been home at night by 18.30 rather than after 19.00 with the queuing to get on the M8 at night.
I look forward to seeing some radical action to deliver fast P&R buses from place with parking on working days (EuroCentral, Ballieston Vue Cinema, The Fort Retail Park, Braehead Retail Park) as the work on the Woodside Viaduct and 'fragile' retaining walls on Charing Cross Cutting hits with closures and restrictions for the next 5 years, & see if this can break some commuter 'habits' (Braehead to Shields Road Subway Station - 8 minutes with perhaps 2-3 buses as SVR to run a 10 minute frequency service.... then walk, hire bike or subway to city centre