GA pilot reported descending below assigned altitude during IFR flight to vcb.

Attributes
ACN	1435414
Time
Date	201703
Local Time Of Day	1201-1800
Place
Locale Reference	CVB.Airport
State Reference	CA
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	PA-28 Cherokee/Archer/Dakota/Pillan/Warrior
Operating Under FAR Part	Part 91
Flight Phase	Descent
Route In Use	Visual Approach
Flight Plan	IFR
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Commercial Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 9 Flight Crew Total 435 Flight Crew Type 36
Events
Anomaly	Deviation - Altitude Excursion From Assigned Altitude

Narrative:

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.

Original NASA ASRS Text

Title: GA pilot reported descending below assigned altitude during IFR flight to VCB.

Narrative: 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.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.