diff --git a/ox/net.py b/ox/net.py
index 4d58bad..bb8e086 100644
--- a/ox/net.py
+++ b/ox/net.py
@@ -113,14 +113,15 @@ get_url = read_url
 def save_url(url, filename, overwrite=False):
     if not os.path.exists(filename) or overwrite:
         dirname = os.path.dirname(filename)
-        if dirname and not os.path.exists(dirname):
-            os.makedirs(dirname)
+        os.makedirs(dirname, exist_ok=True)
         headers = DEFAULT_HEADERS.copy()
         r = requests.get(url, headers=headers, stream=True)
-        with open(filename, 'wb') as f:
+        filename_tmp = filename + '~'
+        with open(filename_tmp, 'wb') as f:
             for chunk in r.iter_content(chunk_size=1024):
                 if chunk:  # filter out keep-alive new chunks
                     f.write(chunk)
+        os.rename(filename_tmp, filename)
 
 def _get_size(url):
     req = urllib.request.Request(url, headers=DEFAULT_HEADERS.copy())