Hannover generally has a safe and secure environment. Petty crimes like pickpocketing can occur, especially in crowded areas or tourist spots. But overall, the places are well lit and the public transport is reliable even at night. As a solo female traveler, it would still be wise to remain cautious and avoid walking alone late at night in unfamiliar areas, just like in any other city. But with street smarts and the usual precautions, one can confidently explore the beauty of Hannover.