My commute involves a daily trip over 4 miles of gravel roads sometimes these roads are very dusty would that be consider ?extreme conditions? which would require shorter service intervals?
There’s pretty much no such thing as normal driving - all driving, or almost all, falls under the severe duty schedule. So no matter what, follow the severe duty maintenance schedule.
Yes, this is what they mean by extreme or severe conditions.
The manufacturer’s Maintenance Schedule should list factors that comprise “extreme service” or “severe service”. Frequently, these factors are listed as footnotes to the regular maintenance schedule, and thus, are not always easy to understand.
When you read all of the various factors that car manufacturers consider to be extreme service, you will realize that virtually everyone’s usual driving patterns fall into this category in one way or another. These factors include: Driving on dusty roads, a lot of stop and go driving, a lot of high-speed driving, a lot of mountain driving, driving in consistently low temperatures, driving in consistently high temperatures, driving in consistently wet conditions, carrying a heavy load, trailer towing, etc, etc.
In other words, unless you can consistently drive at a steady speed of…perhaps 40-50 mph, without exposure to any extreme weather conditions of any kind, with no hill-climbing, no dust, no heavy loads, then you can ignore the extreme service schedule. On the other hand, if you are like 99% of the drivers on the road, you should maintain your car according to the extreme service schedule.