You might consider one of these.
videotrack | B&H Photo Video
This is an audio recorder with limited video capability. It is being closed out because the video is not up to customer (modern HD) expectations. The good news is it has a very good audio recording system - I have one that I use to record live music with and am very happy with it. The mic is not real good at picking up bass (the bass is still there, but it loses balance with the rest of the band), but that will play to your advantage (reduce truck noise) on the street.
If you read the reviews (B&H and Amazon), you will see mixed comments. The issue is it needs to have a fairly recent version of firmware flashed (I hope I'm using the right terms). Mine was current so I did not need to flash.
So, this will save you some money, but be sure to put it through the paces right after it arrives (B&H has 30 day satisfaction policy, Shipping is free to you, but you would probably be out for return shipping - not much for this item) - you need to be comfortable with flashing it if you get an older version of the firmware.
If it works well (and I believe you'll be thrilled), you might want to order a back up. At $30 a pop, they won't last forever.