If you use a voice you can tell them which side you are going to come past on. If it's just a noise, they don't know and could very well move into your way.
The survey is rather limited - only up to more than 3 times a week exercise - many on here do far more than that. Sometimes I run outside, and sometimes I go to a gym but could only pick one. Sometimes I run on a footpath,sometimes I run in a park, sometimes I run on a footpath in a park, but mostly I just run on the road and there was no option for that.