Previous Value Best Method

I'm not really strong in SQL. My goal is to compare the beginning mileage of a vehicle record with it's previous ending mileage reading. I have something that works, but it feels clunky. I wonder if there is a better method, ie a join. Here's what I have:

SELECT A.Trolley_num, A.Date, A.Speedo_start, A.Speedo_end,
(SELECT B.Speedo_end FROM Daily_Trolley AS B
WHERE B.Trolley_num = A.Trolley_num
AND B.Date =
(SELECT Max(Date) FROM Daily_Trolley AS C WHERE C.Trolley_num = A.Trolley_num
And C.Date < '1/23/2005')) AS PrevSpeedoEnd
FROM Daily_Trolley AS A
WHERE A.Date='1/23/2005'

ps: I inherited this db; I'm aware that "Date" should not have been used as a field name.