pythonでWebスクレイピングをしたいがドライバがうまく読み込まれない

pythonでWebスクレイピングしたいのですがドライバがうまく読み込ません。
やりたいことはGoogleのトップをChromeブラウザで開くだけです。

mecahnizeTest.py

python
1from selenium import webdriver
2 
3browser = webdriver.Chrome()
4browser.get('http://google.com')

コードはとりあえずこれだけです。

mecahnizeTest.py及びchromedriverは/Library/python/2.7/site-packagesに配置しています。

エラー文です

Traceback (most recent call last):
  File "mecahnizeTest.py", line 3, in <module>
    browser = webdriver.Chrome()
  File "/Library/Python/2.7/site-packages/selenium/webdriver/chrome/webdriver.py", line 69, in __init__
    desired_capabilities=desired_capabilities)
  File "/Library/Python/2.7/site-packages/selenium/webdriver/remote/webdriver.py", line 98, in __init__
    self.start_session(desired_capabilities, browser_profile)
  File "/Library/Python/2.7/site-packages/selenium/webdriver/remote/webdriver.py", line 188, in start_session
    response = self.execute(Command.NEW_SESSION, parameters)
  File "/Library/Python/2.7/site-packages/selenium/webdriver/remote/webdriver.py", line 254, in execute
    response = self.command_executor.execute(driver_command, params)
  File "/Library/Python/2.7/site-packages/selenium/webdriver/remote/remote_connection.py", line 464, in execute
    return self._request(command_info[0], url, body=data)
  File "/Library/Python/2.7/site-packages/selenium/webdriver/remote/remote_connection.py", line 488, in _request
    resp = self._conn.getresponse()
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/httplib.py", line 1132, in getresponse
    response.begin()
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/httplib.py", line 453, in begin
    version, status, reason = self._read_status()
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/httplib.py", line 417, in _read_status
    raise BadStatusLine(line)
httplib.BadStatusLine: ''

エラー文がいまいち解読できておらずどういうことなのかわかりません、原因はドライバがうまく読み込めていないことだと思うのですが・・・
対処法があれば教えてください、よろしくおねがいします。

環境
Python 2.7.10
Mac OS X Yosemite
Google Chrome