Flight Crew Commercial; Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 9; Flight Crew Total 435; Flight Crew Type 36
Deviation - Altitude Excursion From Assigned Altitude
Human Factors
For a visual approach to KVCB; I had been cleared to descend to 3000 MSL. Passing above KSUU's Class D airspace at 3000 MSL; I was asked by Travis Approach to notify when I had KVCB in sight. Unfamiliar with the area; I had difficulty locating KVCB but was aware I was getting very close.I mistook Vanden Road and its adjacent train track for Interstate 80; in part because in the vicinity of KVCB these routes are on opposite sides of the San Francisco sectional chart and in part because recent suburban development in the Fairfield-Vacaville area doesn't match the yellow fill on the sectional chart.As a result; I thought I was about 4nm closer to KVCB than I really was; and I began a descent. Still without the airport in sight; I neglected to advise Travis.At 2500 MSL; Travis reminded me that I had been assigned 3000. I quickly climbed back to 3000. Shortly after leveling off at 3000; I spotted KVCB; advised Travis; canceled IFR; and completed the flight.
GA pilot reported descending below assigned altitude during IFR flight to VCB.