The most intriguing feature along Route 81 is probably the 5-ramp interchange with Route 9 (shown) with direct access to 9 north from 81 north.
A Route 81 freeway plan exists only in fiction: the plot of T. E. D. Klein's short story "Petey" hinges on a state plan for upgrading Route 81.
(In some editions, including the "Dark Gods" collection, the highway is instead Route 501; but Route 81 is more appropriate for the story's Clinton or Killingworth location. I do not know which number was used first. Did 81 replace 501 for verisimilitude; or did 501 replace 81 to minimize any potential notoriety for the fictional "highway department" that some would read as ConnDOT? SR 501 is the once-planned I-84 spur into West Hartford Center.)