Except in Amish communities, horse drawn carriages were mostly phased out by 1930. For a few years durng the first part of WW2, my family did use a horse carriage and it was the only one in the township.

Carriage blankets served 2 puropses: (1) to keep muck off clothing and wearer, and (2) warmth during cold weather. An effective winter blanket had to be large enough to wrap a seated wearer from shoulders to toes; Another version covered from the waist to toes. A smaller model might be used to wrap a child.

What is the size of your blanket? Is it large enough to have been a carriage blanket?

Because most establishments that suppplied buggy whips and horse-themed travel accessories were out of business by 1920, your blanket likely predates 1920.

Way back when....thinking it was pre 1945....there was always a "carriage robe" as my parents called it, in the back of the car. As I recall, heaters in cars of that era didn't work very well in the back sear, and a robe was kept there to keep the back seat passengers warm during a winter ride. and because cars of that era didn't have turn signals, the window was opened often to signal a turn or a stop. There were even lap blankets that came with the car...likely for a price, but they sometimes carried a label...like Cadillac.
Not saying yours is that "new"...but just remembering that carriage robes didn't go out with automobiles.

Sleigh driving was also a use for those blankets.
Does your's by any chance have a label on it? The Chase Company was one...linked below. And the is a resurgance of carriage driving these days, as a hobby, and of course all things associated with it have become of more interest.
Linda C

Here is a link that might be useful: About lap blankets.

You might consider that some of those scratchy 'wool' blankets might not be wool. I have a horsehair bed blanket. You certainly don't want it next to your skin, but it's extremely warm.

The first automobiles were completely open (horseless carriages) and open touring cars were the rule for most families until the mid twenties. Glassed-in coupes were considered death traps in accidents because safety glass was yet to be invented. Even if you had a closed car, as stated the heat may be non-existant (gasoline stoves were the first car heaters) and the idea of weatherstripping the doors and windows was not full developed, and roofs were painted canvas inserts. Windshields were designed to hinge open, so there were drafts there, too. The modern idea of a snug car was not fully realized until post WWII.
Casey

i have a blanket from my grandparents, does anyone know approx what the value of it would be ? thank you

My grandma used to tell us how her dad used the blanket to keep the horse warm while they were in church. Then they had a smelly blanket to ride home under but they loved their horse and didn't want him standing in the winter without a blanket on. This was around 1903-1911 in Minnesota.

Poor old Dobbin! I could never have a thing like that around, I prefer live, breathing horses.

Casey