1990s would be pretty the same as today.
Road centre lines are yellow. Outside and lane dividing markings (between lanes of the same direction) and basically all other markings are white.
Solid lines indicate no passing/lane changing. Dashed lines are used where passing (on two lane country roads) is safely permitted and for lane dividing markings. In the city the yellow centre line would be a single solid yellow line everywhere.
Chris van der Heide
My Algoma Central Railway Modeling Blog
Here's a LINK to the history of highways in Ontario.
I haven't read through it yet, so can't say for sure if the info you need is included.
EDIT: Here's ANOTHER LINK covering pavement markings in Ontario.
Wayne
I lived near International Falls Minnesota for a long amount of time in my younger years at the end of the 70' and some of the 80's. I returned to that area for a period of time in the 90's.
Many times we would go across the boarder into Fort Frances, Ontario and travel down the highway to Mcdonalds as they didn't have one in International Falls at the time. I also would travel to Sioux Narrows Ontario, my favorite place to go, Beautiful.
The road lines were basically the same as Minnesota. Yellow lines separating traffic with a different direction. White Lines separating traffic of the same direction. It was legal to pass cars on either yellow or white dotted lines. It was illegal to pass cars on either yellow or white solid lines. Double yellow lines were on hills on the highways. Sometimes white lines were double, sometimes single. I never knew the reason for this but it was illegal to cross either.
It was thought by us, the single white lines could be crossed if you needed to change lanes to make a turn off the roadway but you could never cross a double line anywhere. These are all my recollections as it was a long time ago.
This area of Ontario was CN, Hope this helps.
TF
Hello folks.
Can someone tell me what the color of the center line is on roads in the Greater Toronto area in the 1990's, On some photo's they appear to be yellow and on others, white. Is this the case??? If so why the difference. Here in the UK, center line(s) are white and kerb side lines are generally yellow to indicate parking restrictions.
Any advice would be greatly received.
Many thanks Colin