Is Kiambu safe for solo female travelers?

Locals can be a little bit reserved compared to Nairobi and bigger tourist hotspots, but they're welcoming nonetheless. Public transport tends to be safer, just ask for the driver (they'll be in a light blue shirt and navy blue trousers - it's their uniform on weekdays while on the clock) and let them know where you're alighting. They're very helpful with that. Just like everywhere else you travel, you still have to be vigilant.