Bigfoot prints? Or just big footprints

Bigfoot sightings and encounters are definitely no stranger to the Michigan countryside, especially in rural settings where much of the backdrop is corn and other various types of agricultural fields.
Last night, my daughter and I decided to take a relaxing walk in the fresh evening air to get some exercise.
We live right on the outskirts of town. Nixon Road, in Ann Arbor, turns from suburbs right into farm country after our driveway.
As a researcher and a naturally curious person, I almost always have my nose to the ground, so to speak. And last night, I was very glad that I do that.
At around 8:15 pm, our leisurely walk turned into a mini expedition.
As we were walking and chatting, I happened to glance to my right and see a couple little scuff marks by the guardrail next to the road. Something about it looked odd, but I couldn't put my finger on it. To my surprise,when I looked closer and to just the other side of the guardrail, there was a very large footprint coming up the embankment of the small overpass and looking like something had taken a step over the guardrail and across the road, coming out of the cornfield that sits just off the road and down the embankment.(The corn doesn't appear to have started growing in this year yet as you can see by the pictures below)
Since it did rain earlier yesterday morning and afternoon, I'm thinking this footprint had been made fairly recently or it would've been washed away with the rain or at least more eroded than it appears in the pictures.
My daughter and I walked the rest of the way home, and I grabbed my digital camera and went back to take the pictures you see below.
If someone hoaxed these, they were in for a long wait, because the footprint was not easily visible to someone who doesn't have their nose to the ground like I usually do.
Being a small but fairly busy country road as far as vehicle traffic, I don't think someone would set up a hoax there. There isn't much in the way of foot traffic at all. Its dangerously cramped at that overpass. It's cramped to the point that in some areas you have to step off into the grass when a car comes by to avoid being hit. It just does not seem a likely place to play a practical joke. Whether this is an actual print from a large upright creature or not is anyone's guess. It could simply be a weather erosion pattern, a different type print that spread and faded, or nothing more than the imagination of a passionate cryptozoologist on an evening walk with her daughter down an old road in Ann Arbor, Michigan.
You be judge,Haven fans.

Picture 1. Guardrail and print. Facing direction footprint was coming from.(Pics 1, 2, and 3 taken today-June 14,2009-to show surrounding area)

Picture 2. Guardrail with field in background. Facing where footprint was coming from.

Picture 3. Cornfield

Pictures 4,5,and 6. Footprint with dollar bill for comparison.(Note that only 4 toes are clearly visible)