Kerry and I have been talking about differences among various groups of drivers.  Acknowledging that these are very broad generalizations, we've made these observations:

1.  Semi drivers, as a group, are the most courteous.  They are the most likely to move completely over into the next lane to pass.  They are the most likely to wait patiently until it is clear for them to pass.  They often return the waves we give to drivers who pass safely.  A notable exception to this is the subgroup of log truck drivers.  Many of them pass closely, don't slow down at all and just are generally rude about sharing the road.

2.  Drivers of various commercial vehicles are also usually polite and safe passing and sharing the road.  They don't wave back as much as semi drivers.

3.  Passenger vehicle drivers are hard to generalize about.  Most are courteous and patient, but some are just hostile.  We get friendly waves and smiles and people who want to roll down their windows and talk to us at red lights.  People who buzz us closely, rev up their engines to pass or shout obscenities are very infrequent.  We've never had anything thrown at us.  People in beat up old cars are more likely to be rude or dangerous.  Most pick-up drivers are nice.

4.  There are two vehicle types whose drivers we always are very cautious about - school bus drivers, which seems surprising, and RV drivers.  School bus drivers simply won't change lanes to pass.  Many RV's seem to be driven by people (almost all men) who have no idea how wide their vehicle is or where they are on the road.  They tend to pass very close, oblivious to us.  It isn't the same as the rude drivers who pass close and fast just to be jerks.  These guys just don't seem to realize what they're doing.  (I know the Millers can relate to this.  I feel bad that your RV encounter happened in our beautiful home state.)

5.  We certainly find varying responses to cyclists in different states.  To avoid causing any offense, I'll only mention the states we find usually good for cyclist/driver interactions.  So far, rural southern and central Illinois has been full of courteous, safe and friendly drivers.  We've found the same thing in Indiana, Iowa and Minnesota.  Maybe farmers are just nice people.  Maine, Wisconsin and North Carolina have generally friendly drivers.  And Canadians behave in their cars just as they do in their other interactions - friendly, polite and concerned for the welfare of others.

So, other cycle tourers, do you agree, disagree or have any observations of your own to add?  We'd love to hear your response to our experiences with sharing the road.