Good point Topic Map

because: trend of the market
- because: environmentally friendly
  - but: Toyota's Prius causes many damages to environment
    - because: causing acid rain
      - because: spreading sulphur dioxide
        because: nickel mining and smelting produce SO2
  - because: more energy efficient
    - because: two engines to get most efficient results
      - because: reduces energy loss with less ICE load
        because: ICE can operate in optimal condition
    - because: rechargeable electric batteries
      - but: Prius consumes more energy in total than a Hummer
        because: Prius registers a higher energy-cost per mile
  - because: hybrid emits up to 90% fewer pollutants
    - because: reduce emission: shut down ICE at idle
    - because: hybrid engine consumes less fossil fuels
      - because: powered by 2 engines

but: insecure, dangerous
- because: high voltage is a potential danger
  - because: dangerous electrical wires may be exposed
- because: less protection
  - but: toyota's Prius: 5 stars rating in protection
  - because: hybrid cars are lighter

In the near future, hybrid vehicles will dominate the automotive market

but: electric vehicles may dominate auto market
- because: electric vehicles are on the roads now
- because: electric cars better acceleration than petrol cars

because: government and business incentives
- because: employers give cash incentives and reimbursement
- because: e.g. tax rebate in Ontario
but: higher maintenance cost
- because: new to the market, less replacement out there
but: 4-5 times more expensive than conventional cars
because: hybrid car is more economical
but: hydrogen vehicles may dominate the auto market
- but: many technical challenges to overcome