Después de leer la definición:

http://www.westernsnowandice.com/co-sing-tand.asp
The alley dock tests an operator’s ability to back the vehicle into a confined space. The operator must drive into the space without hitting the sides and must stop as close to the back barricade as possible without hitting it (100 points within 6” and 100 points for avoiding rails & barrels).

Encontré:
"Entrar en un callejón" como traducción de *alley dock* en
http://www.lowestpricetrafficschool.com/handbooks/cdl/sp/12

12.2.6 **Alley Dock**. You may be asked to sight-side back your vehicle into an alley, ... www.lowestpricetrafficschool.com/handbooks/cdl/en/12/2

Suerte!