When you are riding with traffic is the traffic in the opposite direction also congested? I ask because if the traffic if light going in one direction you can take the lane and force the traffic to cross the double stripes to pass you.

Taking the lane is about the only option you have. If the traffic laws in your area allow it then you are legally entitled to take the lane, forcing traffic to move over to pass you.

If you're not comfortable with that there's always that narrow patch of grass next to the road. If you're riding a MTB with wide tires you could ride on that. Again, it's only 1.5 miles, so you could get to know that patch of land pretty well to avoid ruts and holes.

Good luck!