A Trimeric on Acrophobia:

 Terrorized Car Passenger High Above the Columbia River

Riding high above the water
Muscles tensing,
Mind predicting
Fearing falling, falling, falling

Muscles tensing
Fingers crooking
Grasping door handles
Shallowly breathing

Mind predicting
Calculating miles remaining
Computing the angle climbing
Estimating the distance down

Fearing falling, falling, falling
Stressing, distressing, why did I come
Wanting to jump out of my skin
How much longer?