Let my friend check my locations while I am taking a stranger's car? I am thinking about taking a long-distance rideshare offered by a stranger on Craigslist. 
For safety, I would like my friends to track my location, until I reach the destination and tell them that I safely arrive.


Is it possible to use my Android phone to 


share my location with others during my travel, and 
then stop sharing my location after I arrive?

If yes, does it depend on the signal strength of my mobile carrier along the way? Or does it only rely on the GPS, which isn't affected by mobile signal strength? My mobile carrier uses Sprint network, which usually has worse signal strength than other networks in remote areas.


Thanks.
As there's no on-board feature covering your needs, I'd recommend taking a look at Glympse. With this app you can decide when to start or stop sharing your location, you could even set a timeout. Only you would need to have the app installed, and those you've shared your location to can watch it on any web-enabled device:

Glympse is a fast, free, and simple way to share your location safely using GPS tracking in real time with friends and family!
No sign up required! Only those you share with can view your Glympse from any web-enabled device.

For alternatives, please take a look at my Location Sharing list.
Any solution will depend on your phone having internet access: it can't work with GPS alone. GPS is only a way for your phone to find out where it is: it doesn't itself allow anyone else to know your location. If you go outside of data coverage, your location will stop updating.