Shuttle service, IAD -- BWI?

Is there any regular, direct, not too expensive shuttle service between
IAD and BWI? (No multiple bus/metro/train routings)

(I just spent a frustrating session trying to get this info from the IAD
and BWI official web pages.)

AES wrote:

Is there any regular, direct, not too expensive shuttle service between
IAD and BWI? (No multiple bus/metro/train routings)

(I just spent a frustrating session trying to get this info from the IAD
and BWI official web pages.)

It's about 60 miles between the two airports, and there is no direct bus
service sponsored by the airport authorities or transit companies.

A number of private shuttle companies, like SuperShuttle, offer nonstop
services, which cost $70 to $80 each way.

Here is an example:

http://www.supershuttle.com/HowItWorks.aspx

They charge $72 for the first passenger, and $10 for each additional
passenger in your group. It's best to make a reservation ahead, but you can
also just show up.

Using transit will require three to four changes along the way, depending
on the route you choose. Price is about $25 per person