Hey
I've had a very quick look at your code, if you're trying to store all the different values in type_of_accident check boxes i think you'll only receive the last one that has been checked from the form. Following example will show you.
<?php
if(isset($_POST['submit']))
{
var_dump($_POST);
}
else
{
print'
<form action="" method="post" target="_self">
test1<input name="test" type="checkbox" value="test1" />
test2<input name="test" type="checkbox" value="test2" />
<input name="submit" type="submit" value="submit" />
</form> ';
}
?>
If your users are only supposed to select one option, you might be better using radio buttons with the same name and different values, if they can select more than one option you'll need to change the names of the check boxes.
Hope this helps
Tim