how can we detect vehicles using matlab

respected sir/mam

i am unable to detect exact number of vehicles in the presence of day light and during the nights.here is my code with which i am working with to tackle this problem.can you please guide me to solve this problem.

clc;
close all;
clear all;
f=imread('C:\Users\Pratyusha\Desktop\project pics\morning 1030\2.jpg');
f=imresize(f,[800 NaN]); 
figure (1)
imshow(f)
g=rgb2gray(f);
g=im2bw(g);
g=medfilt2(g,[5 5]);
figure (2)
imshow (g)
conc=strel('disk',5);
gi=imdilate(g,conc);
figure(3);
imshow(gi);
conc1=strel('disk',5);
ge=imerode(gi,conc1); 
figure(4);
imshow(ge);
gdiff=imsubtract(gi,ge);
figure(5);
imshow(gdiff);
gdiff1=mat2gray(gdiff);
figure (6)
imshow (gdiff1)
gdiff2=conv2(gdiff1,[1 1;1 1]);
figure  (7)
imshow (gdiff2)
gdiff3=imadjust(gdiff2,[0.5 0.7],[0 1],0.1);
figure (8)
imshow (gdiff3)
B=logical(gdiff3);
[a1 b1]=size(B);
figure(9)
imshow(B)
er=imerode(B,strel('line',60,8));
figure(10)
imshow(er)
out1=imsubtract(B,er);
F=imfill(out1,'holes'); 
H=bwmorph(F,'thin',1);
H=imerode(H,strel('line',8,55));
figure(11)
imshow(H) 
I=bwareaopen(H,floor((a1/18)*(b1/18)));
I(1:floor(.9*a1),1:2)=1;
I(a1:-1:(a1-20),b1:1:(b1-2))=1;
figure(12)
imshow(I)
figure (13)
imshowpair (f,I)
Iprops=regionprops(I,'BoundingBox','Image');
hold on
text(8,785,strcat('\color{green}Cars Detected:',num2str(length(Iprops))))
hold on
for n=2:size(Iprops,1)
rectangle('Position',Iprops(n).BoundingBox,'EdgeColor','g','LineWidth',2);
end
hold off