That wouldn't get you down a block in the suburbs.

Problems I see:

1. Vertical alignment of front-mounted weapon.

   a) The chainsaw blade will most likely only impale through a zombie's midsection. Increased weight and obstacles to motion. Proximity to active zombie. Requires abandonment of vehicle. Wasted time and effort in manufacture. Loss of valuable weapon/fuel.

   b) If zombie is not impaled, motion of chainsaw blades will channel detritus directly into wheel path. Increased obstacles. Potential loss of control-potentially fatal if in infested area. Potential loss of vehicle, weapon and fuel. SECONDARY: Active upper body of zombie would travel over handle bars, directly at pilot. Potentially fatal.

2. Weapon placement and choice.

   a) Chainsaw is not mounted at head level (assuming a recently reanimated standing zombie at full average human height). Ability to neutralize zombie on first hit very low. Possible second hit at kneeling/crawling zombie more likely to permanently neutralize threat. Possibility of second pass not likely in escape/threat scenario. b) Chainsaw's destructive power and wide threat response arc (180 degrees or more with average/alert wielder) is limited to directly in front of vehicle. Incapable of using arm strength, forward thrust must come from vehicle. Thrust reliant on forward momentum. Ability to gain/regain momentum after low-speed impact unlikely. Potentially fatal in infested areas.

   c) Chainsaws gyroscopic action creates hindrance to steering. Reduced ability to turn and recover from collisions. Weapon's effectiveness reduced. Increased potential for pilot error. Potentially fatal.

   d) Safety shut-off switch difficult to operate. Either hand positions create problems. Hands on bicycle handlebars increase ability to pilot vehicle but render the chainsaw harder to stop. Potential self-inflicted injury (likely catastrophic) during crash or loss of control, or injury to fellow survivors. Hands on safety shut-off during vehicle operation increase weapon control, but decrease ability to pilot vehicle. Increased likelihood of crash.

3. Vehicle

   a) Low maintenance. Non-fuel reliant. Excellent traits in vehicle for post-civilization survival. Saves fuel for generators or heating. Low-skill threshold for operation and repair. More energy efficient than walking.

   b)DRAWBACKS: Cannot carry substantial cargo. Ability to carry any cargo negatively affects mobility directly. Increased energy expenditure could create lapse in judgement. Offroad ability in question directly relating to type of bicycle. Punctures likely. Potentially fatal in infested area.

   c) Open operator vulnerable to attack from all sides. Lack of protective barriers in front or sides. Easily knocked over. Potentially fatal.

   d) Easily accessible drive mechanism. Can be easily disabled from debris or zombie interference. Vehicle can be rendered inoperable. Potentially fatal. Loss of vehicle and equipment.

SUMMARY: Aesthetically pleasing and intimidating, but only to human subjects. Possible boosts to morale. INEFFECTIVE: High chance of failure, due to user error or failure to effectively neutralize threat. Gross misappropriation of valuable goods in survival scenario. Undue risk and vulnerability from use.