Two driving simulator experiments were conducted to assess different alternatives of lane departure warning and assistance systems. In the first experiment, two types of Lane Departure Warning system (LDW) were compared with one Lane Keeping Assist system (LKA). In the second experiment, the benefit of an LKA was assessed as compared with the condition of no LKA. In addition, similar steering wheel support as for lane departures was implemented as a Lane Change Decision Aid system (LCDA) in the second experiment, giving feedback in so called blind spot situations. The purpose was to investigate the possibility to have the same type of support for different lateral threats in order to harmonize and simplify the overall support given to the driver. Results indicate some deviating driving behaviour for novice drivers and generally a positive objective and subjective results supporting LKA consisting of a combination of guiding steering force and vibrations of the steering wheel.